Employment
6. Topographical Anatomy and Operative Surgery of Pelvic Walls and Organs.
Topographical Anatomy and Operative Surgery of Lumbar Region. Surgical Anatomy
of the Vertebral Column, Spinal Cord and its Meninges.
PELVIC BONES
The complete bony ring which forms the pelvis, so
named because of its resemblance to a basin, is composed of 2 hip bones,
anteriorly and laterally, and the sacrum and the coccyx, posteriorly. The
cavity thus created is divided into a smaller inferior portion called the true
pelvis and a larger superior one, the false pelvis. The line of
separation between these two is the iliopectineal line. The side walls
of the true pelvis are formed largely by the pubes and the ischia; the side
walls of the false pelvis are formed by the ilia. Distinct differences exist
between the male and the female pelves. The female pelvis is distinguished from
the male pelvis by the following features: its bones are more delicate, its
depth less, the entire pelvis is less massive, its muscular impressions are
less marked, the anterior iliac spines are more widely separated, the superior
aperture of the lesser pelvis is larger and more circular, the obturator
foramina are triangular, the coccyx is more movable, and the pubic arch is
wider and more rounded, forming an angle rather than an arch. In brief, the
female pelvis appears to be wider, more shallow and more graceful.
HIP BONE Galen wrote that since the hip bone
resembles no commonplace object, no name had been given to the bone; therefore,
it became known as the innominate or unnamed bone. It consists of 3
parts: the ilium, the ischium and the pubis. These meet at the acetabulum. Up
to the age of 12 the connecting piece is a triradiate segment of cartilage
which begins to ossify at about this period; ossification usually is complete
by the age of 16.
downward where the
ilium joins the ischium and the pubis.
The iliac crest is
the arched upper border which is easily felt in the living subject at the lower
limit of the waist. Its margins are called the outer and the inner lips, and
the interval between them is called the intermediate area. The highest point of
the crest is at its middle and toward the back; this marks the level of the
body of the 4th lumbar vertebra. The iliac crest is crossed by cutaneous
nerves; since no muscles cross it, the deep fascia attaches here. It terminates
anteriorly in a small tubercle called the anterior superior iliac spine, which
is an important surgical landmark and can be felt easily at the upper end of
the fold of the groin. The crest terminates behind in a sharp posterior
superior iliac spine which can be felt on a level with the 2nd sacral
spine, at the bottom of the small dimple which is visible in the upper and the
medial part of the buttock. The tubercle of the crest is a tiny
projection on the external lip; it is palpable about
FIG. The innominate (hip) bone. It consists of 3 parts (the ilium, the
ischium and the pubis), which meet at the acetabulum. approximately at the
level of the body of the 5th lumbar vertebra.
Borders. The
anterior border of the ilium is concave and extends from the
anterior superior spine to the iliopubic eminence, which marks the junction
between the ilium and the pubis. This border is subdivided into 2 equal
concavities by the anterior inferior iliac spine, the latter being too deeply
situated to be palpable through the skin; the iliopsoas leaves the abdomen
through the notch between it and the iliopubic eminence. The posterior
border extends from the posterior superior iliac spine toward the ischial
spine through a point on the margin of the greater sciatic notch opposite the
middle of the acetabulum. It is subdivided into 2 unequal concavities by the posterior
inferior iliac spine, which lies at the posterior limit of the sacro-iliac
joint about
ISCHIUM The ischium consists of 3 parts: a body
which adjoins the ilium, a tuberosity projecting downward from the body and a
ramus (inferior) which passes from the tuberosity upward below the obturator
foramen. The body is triangular on cross section and therefore presents 3
surfaces which are separated by 3 borders. The borders are parts of the margin
of the obturator foramen, the acetabulum and the greater sciatic notch. The
surfaces are pelvic (medial), acetabular (lateral) and gluteal (posterior). The
tuberosity (tuber ischii) is an oval mass of bone which caps the posterior
aspect of the lower part of the body of the bone. The upper part of the medial
border is crossed by the tendon of the obturator internus; it is smooth, is
covered by a bursa, and it forms part of the lesser sciatic notch. The lower
part of the medial border is a rough crest for the attachment of the
sacrotuberous ligament. The lateral border gives origin to the quadratus
femoris, and between this and the acetabulum the groove for the obturator
externus is located. Its chief function is to support the body weight when sitting.
The ramus of the ischium is a flattened bar of bone that projects forward and
medially from the tuberosity. It joins the inferior ramus of the pubis, and
together these "conjoined rami" form the sides of the pubic arch.
Sciatic
Notches. The greater sciatic notch is a wide gap which
is situated between the posterior inferior iliac spine and the ischial spine;
it is bounded by the posterior borders of the ilium and the ischium. The lesser
sciatic notch is the small gap situated between the ischial spine and the
ischial tuberosity. These notches are converted into sciatic foramina (greater
and lesser) by the sacrospinous and the sacrotuberous ligaments. The floor of
the cartilage-covered surface of the lesser sciatic notch is grooved by the tendon
of the obturator internus.
FIG. The right hip bone: (A) seen from without; (B) seen from within.
PUBIS The pubic bone (L. pubis, adult) has
received its name from that region where the hair develops during adulthood. It
consists of a body and 2 rami (superior and inferior). Body. The body is
the wide, flattened, medial part of the bone, the pelvic surface of which looks
upward and is smooth; it is in relation to the retropubic fat pad and the
bladder. The femoral surface is rough, and the symphysial surface is joined to
the opposite pubic bone by the fibrocartilage and the ligaments of the
symphysis pubis; the lateral border bounds the obturator foramen. Crest. The
pubic crest forms the upper border of the body of the bone and is easily felt
at the lower limit of the abdomen and at the side of the midline. Tubercle. The
crest terminates laterally in the pubic tubercle to which the medial end of the
inguinal ligament is attached. If the hip bone is held in the erect position,
the tubercle and the anterior superior iliac spine are in the same vertical
plane. Rami. The superior ramus has 2 ends, 3 surfaces and 3
borders. The medial end is expanded and becomes the body, and the lateral end
expands and fuses with the ilium and the ischium to form part of the
acetabulum. The upper border is sharp and is called the pectineal line; it
extends from the pubic tubercle to the iliopubic eminence. The anterior border
is a ridge known as the obturator crest; it extends from the pubic tubercle to
the acetabular notch. The inferior border forms the upper margin of the
obturator foramen. The pectineal surface is triangular in shape and is situated
between the pubic crest and the iliopubic eminence; it gives origin to the
pectineus muscle. The pelvic surface is smooth and continuous with
FIG. The sacrum. (A) Seen from in front. (B) Posterior view, a probe has
been placed through the sacral hiatus and into the sacral canal. (C) Seen from
above. (D) Sagittal section showing a needle placed in the epidural space.
the body of the bone; the obturator surface is
the upper boundary of the obturator
foramen. The inferior ramus passes
downward and laterally from the body to meet the ramus of the ischium.
ACETABULUM The acetabulum forms the socket for
the head of the femur. The ilium, the pubis and the ischium meet in the center
of this cavity, and their lines of fusion radiate from the center like the
spokes of a wheel. These lines are visible in the child, but in the adult they
are no longer evident. The acetabulum is directed laterally and downward. It
presents a horseshoe-shaped area which is covered with cartilage, but it leaves
a rough acetabular fossa in the floor which adjoins the acetabular notch (the
gap in the lower part of the cup above the obturator foramen). The transverse
ligament completes the rim and converts the notch into a foramen. The articular
branches of the obturator and the medial circumflex arteries enter the joint
through this notch. The obturator foramen is below the acetabulum and is
closed by the obturator membrane, which is attached to its margins except above
at the obturator groove; through this groove the obturator vessels and nerves
pass out of the pelvis.
SACRUM AND COCCYX The sacrum is triangular in
shape, possessing an upper surface which forms its base and a lower end which
corresponds to the apex; it has pelvic, dorsal and 2 lateral surfaces. The bone
is formed by 5 fused vertebrae. The female sacrum is broader than the male
sacrum and is more abruptly curved below. It is inserted like a wedge between
the 2 hip bones; its base articulates with the last lumbar vertebra and its
apex with the coccyx. The pelvic surface is marked by 4 transverse ridges at
the ends of which are the anterior sacral foramina. There are 4 foramina on
each side; they diminish in size from above downward and give exit to the
anterior divisions of the sacral nerves and entrance to the lateral sacral
arteries. Lateral to these foramina are the so-called lateral parts of the
sacrum. A sagittal section through the center of the bone shows that the bone
is united at the circumference, but that a centrally placed interval is filled
by fibrocartilage. The dorsal surface is convex and reveals the posterior
sacral foramina which are smaller in size than the anterior and transmit the
posterior divisions of the sacral nerves. The inferior articular processes of
the 5th sacral vertebra are prolonged downward as the sacral cornua, which
connect with the cornua of the coccyx.
FIG. The bony structure of the sacrococcygeal region.
The anterior projecting upper surface of the body
of the 1st sacral vertebra is the promontory. The posterior wall of the sacral
canal is formed by the superficial posterior sacrococcygeal ligament where the
laminae of the 5th sacral vertebra are absent. The sacral hiatus transmits the
5th sacral nerve, the coccygeal nerves and the filum terminale.
COCCYX The coccyx is formed from the rudimentary
vertebrae which tend to fuse. The bone has a base, an apex, dorsal and pelvic
surfaces and lateral borders. Its apex points downward.
SACROCOCCYGEAL REGION Toward the base of the
coccyx, where it articulates with the sacrum, 2 lateral bony prominences can be
palpated; these are the coccygeal and the sacral cornua which bound the sacral
hiatus. The hiatus is the external opening of the sacrococcygeal canal. The
termination of the subarachnoid space can be indicated by a line which joins
the posterior superior spines of the 1st and the 2nd sacral foramina. The skin
over the sacrococcygeal region is resistant and thick; it is loose and movable
over the convexity of the sacrum but is bound down in the region of the anal
crease. The inferior portion of the dorsal layer of lumbodorsal fascia forms a
musculo-aponeurotic layer over the sacrum. This fuses with the tendinous origin
of the spinal muscles.
FIG. The sacro-iliac region: (A) cross section; (B) seen from behind.
Sacral
anesthesia is an extradural type which reaches the nerves within
the sacral canal. This produces anesthesia in the perineum and the external
genitalia. In the caudad type of sacral anesthesia the needle is placed through
the sacrococcygeal ligament, into the sacral hiatus and then upward along the
sacral canal for from 3 to
FIG. Sacral anesthesia.
A needle has been placed through the sacral hiatus and into the sacral canal.
The bony roof of the sacral canal has been removed.
SACRO-ILIAC REGION Transsacral anesthesia is
produced by direct injection of the anesthetizing agent into the sacral canal
and around the sacral nerves via each of the posterior sacral foramina. The
sacro-iliac joints include the 3 upper sacral segments and the articular
surfaces of the ilia. The joints act as shock absorbers between the spinal
column and the lower extremities. Although the sacro-iliac articulation is
synovial in type, it permits very little movement. The articular surfaces of
the joint are mainly smooth, but several projections and depressions help to
lock and stabilize it.
MUSCULAR AND LIGAMENTOUS ATTACHMENTS The
attachments to the hip bone can be outlined in the following way:
Ilium: To
the anterosuperior iliac spine: the inguinal ligament, the
sartorius and the tensor fasciae latae muscles. To the outer lip: the
external abdominal oblique muscle, the latissimus dorsi and the fascia lata. To
the intermediate area: the internal oblique muscle. The ligaments that
resist sacral rotation. To the inner lip: the transversus abdominis
muscle, the quadratus lumborum muscle and the iliolumbar ligament. At the inner
lip the transversalis fascia becomes continuous with the iliac fascia. To
the posterosuperior iliac spine: the long posterior sacro-iliac ligament. To
the posterosuperior and the posteroinferior iliac spines: the piriformis
muscle. To the antero-inferior iliac spine: the straight head of the
rectus femoris muscle and the iliofemoral ligament. To the gluteal surface: the
reflected head of the rectus femoris muscle, the gluteus minimus, the gluteus
medius and the gluteus maximus muscles. To the upper part of the iliac
fossa: the iliacus. To the iliac tuberosity: the sacrospinalis
muscle and the posterior and the interosseous sacro-iliac ligaments. To the
auricular surface: the anterior sacro-iliac ligament. Ischium and Pubis:
To the ischial tuberosity: the quadratus femoris, the sacrotuberous
ligament, the semitendinosus, the long head of the biceps and the adductor
magnus. To the ischial spine: the gemellus superior and the gemellus
inferior muscles, the levator ani, the coccygeus and the sacrospinous ligament.
FIG. Muscular attachments to the iliac bone: (A) seen from without;
To the pelvic surface of the ischium
and the ilium: the obturator internus. To the body of the
pubis {pelvic surface): the levator ani, the puboprostatic ligament and the
adductor longus. From the region of the symphysis and the inferior ramus: the
gracilis, the adductor brevis and the obturator externus. The adductor magnus
originates at the lower end of the ischium medial to the gracilis. The crus
penis, the ischiocavernosus, the superficial transverse perinei, the perineal
membrane, the sphincter urethrae, the deep transverse perinei, the falciform
process of the sacrotuberous ligament and the inferior pubic ligament are also
attached here. To the symphysial surface: the fibrocartilage of the
symphysis and the anterior, posterior, superior and inferior pubic ligaments. To
the crest: the aponeurosis of the external abdominal oblique, the fascia
lata, the conjoined tendon, the pyramidalis and the rectus abdominis muscles
and the transversalis fascia. To the pectineal line: the pectineus
muscle, the pectineal fascia, the reflected part of the inguinal ligament, the
conjoined tendon, the transversalis fascia and the psoas minor muscles. To
the antero-inferior iliac spine: the iliofemoral ligament. To the
obturator crest: the pubofemoral ligament.
PELVIC DIAPHRAGM
MUSCLES The muscles within the true pelvis may be
considered in two groups: (1) two muscles which together form the pelvic
diaphragm and are associated with the pelvic viscera (levator ani and
coccygeus) and (2) two muscles which are associated with the lower extremity
but arise in the pelvis (obturator internus and piriformis). The walls of the
pelvis minor are covered on each side by the obturator internus and posterior
to this by the piriformis; these are referred to as the pelvifemoral group of
muscles. Therefore, the walls of the pelvis are padded by muscles of the thigh,
since both the obturator internus and the piriformis insert into the femur.
They are covered by fascia, which will be discussed subsequently.
Obturator Internus Muscle. This
muscle covers the inner aspect of the pelvis. It arises from the pelvic surface
of the obturator membrane and from the pelvic surface of the hip bone behind
the obturator foramen. In its posterior part the muscle extends up to the
iliopectineal line. Its upper border recedes and falls short of the upper
margin of the obturator foramen; thus, the obturator vessels and nerves can
leave the pelvis without having to pierce it. The muscle bundles converge
toward and almost fill the lesser sciatic foramen; the converging tendon bends
sharply at the margin of the foramen and inserts on the medial surface of the
greater trochanter just above the trochanteric fossa. It acts as an external
rotator of the thigh. The nerve supply of the obturator internus muscle has
been referred to as a "special nerve" which arises from L 5 and S 1
and 2.
Piriformis muscle (S
1 and 2). Like the obturator internus, this muscle arises from the
osseoligamentous framework of the interior of the pelvis. It lies on the
posterior wall of the pelvis and arises from the 2nd, the 3rd and the 4th
pieces of the sacrum. Its fibers travel outward and converge to form a
musculo-aponeurotic tendon which leaves the pelvis through the greater sciatic
foramen. It inserts into the top of the greater trochanter and, although it
belongs, with the obturator internus, to the pelvifemoral group, nevertheless
it serves a diaphragmatic function, since
FIG. Muscles of the
true pelvis (obturator internus and piriformis). (A) Seen from behind; a
section of the sacrotuberous ligament has been removed. (B) Posterolateral
view.
it is continuous in the same plane with the
coccygeus. In the standing position, the muscle is on the wall rather than on
the floor of the pelvic cavity. It abducts the flexed thigh and laterally
rotates the extended thigh. The pelvic diaphragm is composed of 2 muscles on
each side: the levator ani and the coccygeus. The levator ani may be divided
into 2 parts: the pubococcygeus and the iliococcygeus. The 3 muscles
(pubococcygeus, iliococcygeus and coccygeus) are the original "tail"
muscles which take this origin from the pelvic bone and together form the whole
of the pelvic diaphragm. A distinct space of cleft separates them, but this is
apparent only when the fascia is removed. The levator ani arises from the inner
side of the pubis for a short distance lateral to the symphysis and from the
tendinous arch (white line). The pubococcygeal portion of the levator
ani is placed more medially; its fibers pass in an anteroposterior direction
and insert into a dense ligament behind the rectum. This ligament is known as
the anterior sacrococcygeal ligament and is inserted into the lower two pieces
of sacrum and the upper segment of coccyx. The pubococcygeus muscle has been
termed the "visceral" part of the pelvic diaphragm, since this muscle
fixes the terminal portions of the visceral tubes. There is no hiatus in the
levator surrounding the visceral tubes. Therefore, the implantation of the
medial fibers of the pubococcygeus firmly fixes the viscera and constitutes a
firm attachment. This intimate relationship between the pubococcygeus and the
viscera is of surgical importance in the proper understanding of the mechanics
of surgical repair. The iliococcygeal portion of the levator ani is
placed more laterally and posteriorly than the pubococcygeus, and its fibers
take a more transverse course. It is inserted into the
FIG. The pelvic diaphragm and its fascia. (A) Sagittal section showing
the origin of the levator ani from the arcus tendineum; the arrows indicate the
space which may exist (hiatus of Schwalbe) if the obturator fascia forms a
tendinous sling between the pubic bone and the ischial spine. A hernia could
occur through such a gap. (B) Formation of Alcock's canal; the arrow indicates
the hiatus of Schwalbe. The parietal and the diaphragmatic pelvic fasciae are shown.
sides of the sacrum and into the anococcygeal
raphe. The iliococcygeus has no relation to the organs as they pass from the
pelvis to the exterior; even its most anterior fibers do not reach the anal
canal. In crossing the midline in front of the coccyx, the muscle forms part of
the floor and the wall against which the terminal part of the rectum rests. It
also offers indirect support to the sigmoid and to the jejuno-ileum when the
body is in the standing position. It is of obstetric importance as a support
but of no great importance in gynecologic repairs.
Coccygeus muscle. This
fills the space between the coccyx and the ischial spine. It is of little
importance as a diaphragmatic support but helps to complete or fill in the
formation of the pelvic diaphragm. It is of major importance as a support in
pregnancy but does not suffer in the course of a normal delivery. The obturator
internus, the piriformis and the coccygeus assist the associated ligaments in
maintaining fixation of the sacro-iliac joint by holding the posterior wall of
the pelvis together. Therefore, they are of importance in relation to backache
and so-called sacro-iliac strain.
FASCIA The pelvic fascia, which is distributed in
the basin-shaped pelvis, may be divided into 3 main divisions: (1) the parietal
fascia, which covers the muscles of the pelvic cavity, (2) the diaphragmatic fascia,
which forms a covering for the pelvic diaphragm and (3) the endopelvic or
visceral fascia, which covers the pelvic viscera.
The parietal layer of
the pelvic fascia lines the sides, the back and the front of the pelvic cavity
and covers the muscles which form a padding for this cavity. It forms a rather
firm layer over the muscles but a very thin layer over the periosteum. It is a
downward continuation of the transversalis fascia, and as it enters the pelvis
it attaches on each side to the bone at the linea terminalis (iliopectineal
line). It then continues downward over the obturator internus muscle, forming a
fascial covering for this muscle; it attaches to the bone about the margin of
the muscle. That portion of fascia which overlies the obturator internus muscle
is known as the obturator fascia. Over the upper portion of this fascia
a
FIG. The pelvic diaphragm (levatores ani and coccygei) seen from above.
The pubococcygeus and the iliococcygeus muscles form the levator ani; the
pubococcygeus is the stronger of the two.
FIG. The pelvic diaphragm and its fascia, seen in a frontal section.
FIG. The visceral part of the pelvic fascia. This layer of connective
tissue envelopes the pelvic viscera.
curved line forms as a result of a thickening of
the fascia; this thickened portion has been referred to as the white line or
the arcus tendineum. It is a linear thickening which extends from the
symphysis pubis in front to the ischial spine posteriorly. It does not travel
as a straight line but has a downward directed curvature. From this line the
levator ani muscle and its pelvic fascia covering (diaphragmatic pelvic fascia)
take origin. It is true that in most instances the levator ani arises from the
pubic bone anteriorly, the ischial spine posteriorly and the obturator fascia
between these two points; however, at times the fascia forms a tendinous sling
which attaches to bone only in front and behind. This results in a space which
exists between the sling and the obturator fascia; such a space is known as the
hiatus of Schwalbe. At times an elongation of pelvic peritoneum may
enter the hiatus and into the so-called suprategmental space. If this exists, a
hernia into the ischiorectal fossa may result.
Diaphragmatic Pelvic Fascia. This
fascia forms a sheath or envelope for the levator ani and the coccygeus
muscles. Therefore, it has 2 layers, referred to as superior (internal) and
inferior (external) layers. The superior layer of diaphragmatic fascia
is strong and thick, but the inferior layer is much thinner; the superior layer
is strong enough to give additional support to the structures which rest upon
the diaphragm. The inferior layer is known as the anal fascia; caudally,
it becomes continuous with the superior fascia of the urogenital diaphragm and with
the fascia of the sphincter ani muscle. The levator ani muscles and their
fascial coverings divide the extraperitoneal space on each side of the rectum
into an upper pelvirectal and a lower ischiorectal space, both of which are
filled with fat and areolar tissue. Along the lateral wall of each ischiorectal
space Alcock's canal is found. This canal is formed by a split in the
obturator internus fascia; it carries the pudendal vessels and nerves as they
course horizontally backward.
FIG. Arrangement of structures on the side wall of the pelvis. The
muscles (obturator internus and piriformis) and the sacral nerves are beneath
the parietal layer of pelvic fascia; the internal iliac vessels are above it.
The visceral part of
the pelvic fascia is that layer of connective tissue which envelopes the pelvic
viscera. On each side it is continuous with the fascia on the pelvic surface of
die levator ani muscles and so indirectly becomes continuous with the parietal
pelvic fascia along the origin of that muscle. It forms 3 tubes of fascia which
encase in succession the urethra and the bladder, the vagina and the lower part
of the uterus and the rectum. In each instance, the fascial sheath is in
intimate contact with the musculature of the corresponding viscus and is
believed to receive muscle fibers from it. These fascial tubes are connected by
thickened portions of the visceral fascia ("ligaments"). On either
side of the vagina and the lower uterus the cardinal ligaments extend
laterally to the parietal pelvic fascia. These are the bases of the broad
ligaments and are important in gynecologic surgery; they have also been
referred to as Mackenrodt's ligaments. On each side of the rectum its lateral
ligaments extend backward to the sacrum; they are known as the rectal
stalks. The front of the sacrum also is covered by fascia which passes
behind the rectum and forms a fasciaenclosed space called the retrorectal
space. This space is bounded in front by the fascia on the back of the rectum,
behind by the presacral fascia, and on each side by the lateral rectal stalks.
In the male it forms the important rectovesical fascia and the sheath of the
prostate. The obturator internus and the piriformis muscles are located outside
of (beneath) the pelvic fascia, since they both ultimately leave the pelvis.
The sacral nerves are also beneath this fascia, since the majority of them
leave the pelvis through the sacral foramina. Therefore, it is unnecessary for
these muscles and nerves to pierce the fascia. On the other hand, the blood
vessels of the pelvis (branches of the internal iliac vessels) are destined to
remain in the pelvis and are located inside of (above) the pelvic fascia,
between it and the peritoneum.
PELVIC VISCERA
THE ADULT BLADDER The empty and contracted urinary
bladder has 4 angles, 4 surfaces and 4 ducts, a duct being attached to each
angle. The spelling of each duct starts with the letter "U": 1
urachus, 1 urethra and 2 ureters. The urachus attaches to the anterior angle
(apex), the right and the left ureters attach to the posterolateral angles, and
the urethra attaches to the inferior angle. Surfaces. The 4 surfaces are
the superior, the 2 inferolaterals and the posterior. They are somewhat triangular
in shape and are bounded by the 3 angles which connect around the borders. The
superior surface and about a 1/2 inch of the posterior surface are the only
parts covered with peritoneum. The superior surface is directed upward
and is related to the coils of the ileum and the pelvic colon. In the female,
the uterus lies on this surface and tends to indent it. At its anterior end,
this surface becomes somewhat pointed and forms the apex of the bladder.
This is situated immediately behind the upper margin of the pubic symphysis and
is continuous with a strong fibrous cord (median umbilical ligament) which
passes upward in the midline between the transversalis fascia and the
peritoneum. The inferolateral surfaces are in contact in front with the
retropubic fat pad which fills the space of Retzius. More posteriorly, the
surfaces are related to the obturator internus muscle and the lateral umbilical
ligament (obliterated umbilical artery) above and to the levator ani muscles
below. The numerous
FIG. The urinary bladder. (A) Side view showing the surfaces, the angles
and the "ducts." (B) Malformations of the urachus.
veins of the vesical venous plexus pass backward
and are in intimate relationship with these surfaces. The posterior surface of
the bladder faces as much downward as backward and has been referred to as the base
or fundus of the urinary bladder. It lies in front of the rectum, and it
can be palpated through the rectum. No peritoneum exists between the rectum and
the posterior surface of the bladder, except to a very slight degree above;
however, they are separated from each other by the vasa deferentia, the seminal
vesicles and the rectovesical fascia (Denonvilliers'). The two vasa deferentia
lie side by side on the posterior surface of the bladder and intervene between
the seminal vesicles. The ureters enter at the superolateral angles. Neck. The
neck of the bladder is that part which is continuous with the urethra. In the
male it is embraced by the prostate and in the female it lies on the upper
layer of the urogenital diaphragm (triangular ligament). It is the lowest part
of the bladder and is connected with the lower part of the back of the pubis by
the pubovesical or puboprostatic ligaments. Because of the obliquity of the
pubis in the erect posture, the bladder neck in the male lies a little below
the level of the upper margin of the symphysis and about 2 ½ inches
behind it. The bladder neck rests on the base of the prostate, and its muscle
fibers are uninterruptedly continuous with those of the prostate. The union of
the bladder and the prostate is marked on the outside by a groove in which lie
the veins of the prostatic and the vesical plexuses. These veins extend above
the groove onto the inferolateral surface of the bladder and below it onto the
lateral aspect of the prostate gland. As the bladder fills, the neck remains
fixed, the upper wall rises and, with the other surfaces, increases in area and
becomes more convex. The inferolateral surfaces approximate themselves to a
greater area of the side
FIG. The
urinary bladder seen from above.
walls of the pelvis, the greater vessels and
nerves, and the vasa deferentia. The borders become rounded and obliterated.
The bladder continues to rise out of the pelvis, stripping the peritoneum from
the anterior abdominal wall so that it is in direct contact with the
transversalis fascia for about 1 ½ inchesabove the pubic bone. When
contracted and emptied, the bladder lies in the lower and the anterior part of
the pelvis immediately below the peritoneum in the extraperitoneal fatty
tissue, the areolar element of which becomes condensed to form a sheath around
it. A distended bladder pushes the prostate backward, making it more prominent
on rectal examination; hence, the true size of the prostate can best be
estimated through the rectum only when the bladder is empty.
The prevesical or retropubic space of
Retzius is that space which is behind the pubic bone and in
front of the urinary bladder. The space is bounded anteriorly by the posterior
sheath of the rectus muscle and the posterior surface of the pubis. It is
limited below by the puboprostatic (pubovesical) ligaments in the fascia
covering the levator ani. On each side it extends as far back as the internal
iliac artery and its visceral branches. Superiorly, it is continuous with the
interval that exists between the peritoneum and the transversalis fascia which
extends up to the umbilicus; here it is limited on each side by the lateral
umbilical ligaments. The median umbilical ligament (urachus) bisects it. This
extraperitoneal space is filled with fatty and areolar tissue which separates
the bladder from the ventral pelvic wall. Inflammatory involvement of it may
follow bladder infections and urinary extravasation as seen in extraperitoneal
rupture of the bladder; an effusion into this space may extend into the
extraperitoneal tissue of the abdominal wall or the pelvis. The surgeon may
enter the bladder extraperitoneally through the space of Retzius.
Ligaments. The
bladder is anchored at its base where it is fixed by continuity with the
prostate and the urethra. The latter in turn is fixed to the urogenital
diaphragm (triangular ligament). The neck of the bladder is fused by the puboprostatic
(pubovesical in the female) ligaments. In the female, the visceral
attachments of these ligaments are to the neck of the bladder; therefore, they
have been called the pubovesical ligaments. However, their anatomy is
essentially the same. The medial puboprostatic (pubovesical) ligaments
are thickenings of the pelvic fascia which form a pair of strong thick
bands that fix the prostate and the neck of the bladder. They arise from the
lower part of the back of the pubis at the sides of the symphysis, pass
backward and fuse with the strong fascia that surrounds the base of the
prostate and the neck of the bladder. They form the resisting
FIG. Midsagittal section through the distended bladder. As the bladder
fills, the neck remains fixed; the peritoneum is stripped from the anterior
abdominal wall.
membrane that interrupts the ringers when pushed
down between the bladder and the pubis when one examines the space of Retzius.
A narrow fascial sheath unites each ligament with its fellow of the other side,
and the two form a roof over the anterior part of the gap between the anterior
borders of the levatores ani. The medial puboprostatic ligaments constitute the
strongest, most definite and most important part of the pelvic fascia. They are
continuous laterally with the lateral puboprostatic ligament, which is
that part of pelvic fascia covering the anterior part of the levator ani; it is
connected with the fascial sheath of the prostate and the bladder at the side
of the bladder neck. The bladder is retained in position anteriorly by the median
umbilical ligament (urachus); the lateral umbilical ligaments (atrophied
fetal umbilical arteries) also stabilize the bladder anteriorly. The lateral
and the median umbilical ligaments maintain the bladder against the anterior
abdominal wall when it fills and rises out of the pelvis. Posteriorly, the
bladder is supported by the rectovesical fascia (Denonvilliers').
Coats. The structure
of the bladder reveals 5 coats: serous, fascial, muscular, submucous and
mucous. 1. The serous coat is peritoneum which is restricted to the
upper surface and also to a small part of the base in the male. 2. The
fascial coat is extraperitoneal tissue which sheathes the bladder. It is
loose except on the upper surface where it becomes an exceedingly thin layer
which binds the serous to the muscular coat. 3. The muscular coat is a
thick, strong, nonstriated muscle which is arranged in interesting bundles
traveling in different directions. This is difficult to display in the
dissecting room, but it is arranged in close bundles which pass both obliquely
and circularly around the bladder. At the neck of the bladder these bundles
become massed together to form a ring called the sphincter of the bladder; the
sphincter is continuous inferiorly with the muscular wall of the urethra in the
female and with the muscular substance of the prostate in the male. 4. The
submucous coat is a layer of areolar tissue which forms a loose connection
between the muscular and the mucous coats. The blood vessels and the nerves
ramify in this coat before entering the mucosa. 5. The mucous coat is of
the usual type.
The Interior of the Bladder. If
the bladder is contracted and empty, the mucosa is thrown into folds and
presents a wrinkled or rugose appearance; in the distended bladder, however,
the mucosa becomes smooth. The trigone (trigonum vesicae) is a
triangular area which occupies most of the inner surface of the posterior
bladder wall and remains smooth even when the bladder is empty. It is elastic
and tightly bound by areolar tissue to the muscular coat; therefore, it does
not alter its appearance as does the rest of the mucous membrane. It is thinner
than the rest of the mucosa. When a cystoscopic examination is made in a living
subject, the trigone appears pink because this thinness permits the vessels to
be seen through it. The rest of the mucous membrane of the bladder presents a
straw-colored appearance. The apex of the trigone is formed by the internal
urethral orifice, the base corresponding to a line which passes between the 2
ureteral orifices; it is known as the interureteric ridge. This ridge is
mucous membrane which has been raised by an underlying bar of muscle. The sides
of the trigone are about
If a probe or a catheter is passed into these
openings, it is noted that the ureter takes an oblique course through the
bladder wall for about 3/4 inch. This obliquity forms a valve which allows
urine to pass into the bladder but prevents regurgitation as the bladder fills.
The internal urethral orifice is at the apex of the trigone. It is not
completely circular because behind it an elevation known as the uvula or
vesical crest pushes its posterior margin slightly forward. This uvula presents
a bulging which results from the middle lobe of the prostate; if this lobe
becomes enlarged, it may block the orifice partially or completely. The
retrotrigonal fossa is the interior of the fundus of the bladder. When it
is deepened by increased intravesical pressure (prostatic hypertrophy), urine
may accumulate here and stagnate. Foreign bodies may gravitate into this fossa,
and bladder ruptures can occur through it.
VESSELS AND NERVES
Arteries. The
arterial supply to the bladder is derived mainly from the internal iliac
artery; small branches from the obturator and the internal pudendal arteries
are supplied to the anterior part of the bladder. The superior vesical
artery, which is the unobliterated part of the umbilical artery, supplies
the superolateral wall. The inferior vesical artery is distributed
between the floor of the bladder, the prostate and the prostatic urethra. The middle
hemorrhoidal artery supplies a branch to the posterior surface of the
bladder.
Veins. The veins
form perivesical plexuses which are most dense around the neck and the ends of
the ureters; these drain into the inferior vesical veins. In the male, the
larger veins lie in the groove between the bladder and the prostate and form
the vesicoprostatic plexus.
Lymphatics. The
lymph vessels of the anterior part of the bladder pass to the external iliac
glands. From the posterior part, a few may pass to the external iliac glands,
but the major portion of these drain into the internal iliac glands.
Nerves. The nerve
supply accompanies the arteries and involves not only a complex coordination of
sympathetic and parasympathetic nerves but also the voluntary control of the
sphincter via the pudendal nerve. The sympathetic nerves (hypogastric plexus)
are the "filling" nerves of the bladder, since they inhibit the
detrusor muscle which makes up the bladder wall; they cause increased tone in
the internal sphincter, thereby permitting the bladder to retain its contents.
On the other hand, the parasympathetic nerves (pelvic splanchnic nerves) are
the "emptying" nerves of the bladder because they stimulate the
contraction of the detrusor muscle, the elevation of the trigone and the
relaxation of the internal sphincter. This is accompanied by voluntary
relaxation of the external sphincter by means of cerebral control via the
pudendal nerve.
FIG. Nerve supply to the bladder (diagrammatic).
SURGICAL CONSIDERATIONS
INJURIES TO THE BLADDER Bladder wounds would
occur far more frequendy if the organ were not so well protected within thej
pelvic cavity. These injuries may occur in various ways: as a result of
FIG. Suprapubic cystostomy. (A) A vertical midline incision is made in
the suprapubic region. (B) The muscles and the transversalis fascia are incised
and retracted. The peritoneum is reflected upward, and the bladder is incised.
(C) The completed cystostomy in sagittal section.
laceration by sharp bony fragments in fractures
of the pelvis; from direct blows over the hypogastrium, especially if the bladder
is distended; penetrating wounds account for a certain number of bladder
injuries, as does violence exerted through the rectum, the vagina or the
perineum. The injury may be intraperitoneal or extraperitoneal. Intraperitoneal
rupture occurs in the part of the bladder covered by peritoneum;
extraperitoneal rupture involves only the mucomuscular coats of the viscus,
since these are not covered by peritoneum. In the latter case, the lesion is
subperitoneal, and the urine extravasates beneath the peritoneum. The most
frequent site for rupture of the bladder is the posterosuperior aspect. Whether
the rupture is intraperitoneal or extraperitoneal, immediate surgery must be
employed.
APPROACHES TO THE BLADDER For diagnostic
purposes, the urethral (cystoscopic) approach is employed. The 3 most common
other approaches usually described are the suprapubic (extraperitoneal), the
abdominal (transperitoneal) and a transperineal (perineo-urethral). The
suprapubic approach affords excellent access to the extraperitoneally
placed bladder. It is particularly applicable in prostatectomy and in the
removal of calculi and neoplasms. The abdominal and the transperineal
approaches are more of didactic than practical interest.
SUPRAPUBIC CYSTOSTOMY This operation is
accomplished through a vertical midline incision that is placed in the
suprapubic region. It is preferable to have the organ fully distended as a
preliminary step. The incision is deepened to an interval between the rectus
abdominis and the pyramidalis muscles. Behind these muscles and at the upper
border of the symphysis lies the transversalis fascia. The prevesical space is
exposed by dividing this fascia. If the bladder is distended, it can be felt by
inserting a finger into the lower angle of the incision. The peritoneum is
reflected upward; since the connection between the peritoneum and the bladder
is loose, this maneuver is accomplished readily. The prevesical fat and the
visceral layer of pelvic fascia are incised. Vesical veins may be found in this
stratum. Now the bladder can be elevated and entered. A Pezzer type of catheter
is introduced into the bladder for drainage.
PELVIC VISCERA IN THE MALE The upper part of the
pelvic colon usually can be lifted out of the male pelvis, but the lower part
remains attached to the dorsal wall by the medial limb of the pelvic mesocolon.
The rectum occupies the lower
FIG. The pelvic viscera in the male. The left wall of the pelvis has
been removed, and the bladder is partly filled.
portion of the dorsal part of this cavity and
follows the concavity of the sacrum and the coccyx. The urinary bladder lies in
the lower and anterior part of the cavity behind the pubic bone. Both ureters
usually can be seen shining through the peritoneum posteriorly at the side
walls of the pelvis. The seminal vesicles lie on the back of the bladder
between it and the rectum, and on each side the vas deferens can be seen
through the peritoneum as it passes from the deep inguinal ring toward the
bladder. Having crossed the pelvic brim, the vas first passes downward and
backward and then medially across the ureter to reach the back of the bladder,
where it descends along the medial side of the seminal vesicle close to the
vesicle of the opposite side. The prostate lies below the bladder, directly in front
of the lower part of the rectum, and encloses the prostatic urethra. The pelvic
peritoneum covers the dorsal wall of the pelvis and is reflected off as the
medial limb of the pelvic mesocolon. At the 3rd piece of sacrum, the peritoneum
reaches the rectum, to which it gives a partial covering, and then covers the
front of the upper third of the rectum and its sides. At the middle third it
covers only the anterior surface and the lower end of the middle third as it
passes from the rectum to the bladder. It covers the upper surface of the
bladder, from which it passes forward onto the anterior abdominal wall and the
sides of the pelvic wall. From the sides of the upper third of the rectum it
extends to the side walls of the pelvis, forming the floor of a pair of
depressions called the pararectal fossae. As it continues forward from
the rectum to the bladder it forms the floor of the depression known as the rectovesical
pouch. When the peritoneum reaches the bladder it is tucked behind it to
cover a small portion of its posterior surface in the median plane between the
two vasa deferentia.
DEFERENT DUCTS
The vas (ductus) deferens has
a scrotal, an inguinal and a pelvic course. It begins at the lower end of the epididymis,
passes upward over the back of the testis on the medial side of the epididymis
and ascends to the superficial inguinal ring. It traverses the inguinal canal
as a constituent of the spermatic cord; in the posterior part of the cord it is
readily palpable because of its firmness. It leaves the other constituents of
the spermatic cord at the deep inguinal ring. The intrapelvic portion of each
vas extends from the internal inguinal ring to the base of the prostate. It
hooks around the origin of the inferior epigastric artery and passes backward
with a slight downward bend on the side wall of the pelvis until it reaches the
region of the ischial spines. Here it makes a right angle bend which carries it
medially, forward and downward across the terminal part of the ureter and down
the posterior surface of the bladder. After hooking around the inferior
epigastric artery, it crosses the external iliac artery and vein, the superior
ramus of the pubis, and the obturator internus muscle, but it is separated from
the latter by the lateral umbilical ligament (obliterated umbilical artery) and
the obturator artery, nerve and vein.
FIG. Pelvic viscera in the male, seen from behind.
At the ischial spine, where it turns medially, it
crosses the ureter and then passes downward on the posterior aspect of the
bladder. In this part of its course it lies behind and in front of the rectum
with the seminal vesicle on its inferolateral side and the vas of the opposite
side in close contact with it. Until the vas reaches the posterior surface of
the bladder it is in direct contact on its medial side with the peritoneum, but
thereafter it lies below the peritoneal floor of the pelvis. In its terminal
part each vas is enclosed within the thickness of the frontally disposed rectovesical
fascia (Denonvilliers') and becomes widened into an ampulla. The ampullae
appear as elongated bags which are reservoirs for the semen; it is in the
ampullae that a secretion of the mucous membrane of the vas is added. The vasa
deferentia converge and unite with the excretory ducts of the seminal vesicles
to form the ejaculatory ducts; these traverse the prostate and open into the
prostatic urethra. The artery to the vas deferens arises either from the
superior or the inferior vesical artery, runs in close relationship with the
wall of the vas from the base of the bladder to the epididymis and anastomoses
with the testicular artery.
SEMINAL VESICLES The seminal vesicles are
offshoots of the deferent ducts. They appear as lobulated sacs, about
FIG. The intrapelvic portion of the vas deferens (seen from behind). The
left seminal vesicle and the ampulla of the vas have been sectioned, and part
of the prostate has been removed in order to expose the ejaculatory duct.
FIG. The seminal vesicle. The vesicle has been unravelled. It is a
tortuous tube with many outpouchings.
vessels of the vesicle and the ampulla of the
vas, and end in the internal and the external iliac glands.
PROSTATE GLAND The prostate gland is a solid
organ which surrounds the urethra between the bladder and the urogenital
diaphragm. It consists of fibrous tissue, plain muscle and glandular elements.
It is broader than it is long, being about 1 ¼ inches long and 1 ½ inches broad.
Its exact functions are not known. It adds a secretion which is concerned with
the vitality of the spermatozoa. It has an apex (lower end), a base (upper
surface), an anterior surface, a posterior surface and a pair of lateral
surfaces. It is the size and the shape of a chestnut, surrounds the first WA
inches of the urethra and is traversed by the ejaculatory ducts. The base
or superior surface, although structurally continuous with the superimposed
bladder (neither the fibers nor the muscular part shows any interruption as
they pass from one organ to another), nevertheless shows a circular groove in
which fat and veins are lodged. Its apex points downward and rests upon the
superior fascia of the urogenital diaphragm. Its anterior border or surface is
blunt and rounded and is separated from the retropubic space (Retzius) by the
puboprostatic ligaments and from the lower part of the symphysis by
fibro-adipose tissue and a plexus of veins. The posterior surface is flattened
and rests
FIG. Diagrammatic presentation of relations of the prostate (coronal
section).
against the lower inch of rectum. This is the
portion of the prostate which is felt by digital examination, only the
rectovesical fascia intervening. This surface is pierced on each side of the
median plane by the ejaculatory ducts. The 2 lateral surfaces (inferolateral)
are convex and are supported by the anterior fibers of the levator ani; the 2
anterior borders of the levators clasp the lower part of the prostate between
them. Lobes of the Prostate. In uterine life, longitudinal depressions
appear on the walls of the urethra immediately inferior to the bladder. These
depressions become buds which grow and penetrate the surrounding muscle and the
connective tissue to form the ultimate 5 lobes of the prostate gland: an
anterior, a posterior, a medial and 2 lateral lobes. The anterior lobe buds
from the anterior wall of the urethra; its glandular elements gradually
disappear so that at birth a few or no glandular elements remain. Therefore,
adenomas rarely, if ever, occur in this lobe, and there is no encroachment on
the lumen of the urethra from this direction. The posterior lobe arises
from the posterior wall of the urethra, inferior to the orifice of the
ejaculatory ducts, and grows superiorly to occupy a plane behind these ducts.
As it grows toward the base of the bladder it becomes both posturethral and
postspermatic. This lobe lies behind the middle lobe, forms the entire
posterior surface of the gland and is the lobe encountered during digital
examination. Adenomas rarely, if ever, occur here, but primary carcinoma may.
The 2 lateral lobes arise as tubular outgrowths from the lateral walls of the
urethra. They grow laterally, anteriorly, posteriorly and upward ntil they
occupy almost the entire base upper portion) of the gland. As they grow
nteriorly, they almost approximate one another n the anterior region of the
urethra. Hypertrophy of these lobes causes urinary obstruction by lateral
encroachment on the prostatic portion of the urethra, and if one lobe greatly
exceeds the other in size, the urethra may be pushed laterally and be increased
in length. Clinically, the median {middle) lobe is the most important.
It originates on the posterior surface of the floor of the ejaculatory ducts.
It is posturethral as is the posterior lobe; but, unlike the posterior lobe, it
is prespermatic; it is below the neck of the bladder and contains much
glandular tissue. In this region the subtrigonal and the subcervical glands
(Albarran) are found. These mucous glands are entirely separate and distinct
from the prostate and are important because of their intimate relationship to
the bladder neck. Slight degrees of enlargement of these glands may lead to
obstruction of the outflow of urine. The middle lobe normally projects into the
urethra, causing a prominence on its floor; this prominence is known as the
verumontanum (crista urethralis, seminal colliculus). This lobe is clinically
important because it is the one in which adenomas frequently grow. The line of
least resistance is inward into the urethra. As it enlarges it pushes the
mucous membrane of the urethra ahead of it, extends into the bladder and may
entirely block the internal urinary meatus. The effort of straining to urinate
pushes it onto the internal meatus, thus further blocking the outlet.
Fascial Relations and Capsules. The
prostate has 2 capsules: a true and a false. The true capsule is formed by a
condensation of tissue at the periphery of the gland. The false capsule is
formed by the visceral layer of the pelvic fascia which pro
FIG. The 5 lobes of
the prostate: (A) a cross section at the neck of the bladder of an embryo; (B)
sagittal section of the bladder and the prostate.
FIG. The capsules of the prostate; diagrammatic presentation of the true
and the false capsules in coronal section.
vides a sheath common to both the bladder and the
prostate but is absent where these 2 organs are in contact. For this reason,
adenomas of the prostate grow upward into the bladder, this being the line of
least resistance. A pudendal (prostatic) plexus of veins lies between
the 2 capsules; it receives the deep dorsal vein of the penis in front. During
suprapubic prostatectomy the surgeon enucleates the prostate from within both
of its capsules and in this way leaves the prostatic plexus of veins
undisturbed. During this operation the prostatic urethra is removed with the
gland, and the ejaculatory ducts are torn. As a result of this, the patient,
although not impotent, is sterile. In the fetus the peritoneum of the pelvic
floor extends down as a pouch behind the prostate gland; normally, this pouch
is shut off from the peritoneal cavity and then exists as 2 layers with a
potential space between them. These 2 layers are attached above to the
peritoneum (cul-de-sac of
FIG. Denonvilliers' fascia.
Vessels.
The blood supply of the prostate is derived from the inferior vesical and the
middle rectal (hemorrhoidal) arteries. The prostatic plexus of veins is joined
in front by the deep dorsal vein of the penis. As these veins pass backward
they extend around the junction of the prostate and the bladder and are joined
by numerous vesical veins. They continue backward, lateral to the seminal
vesicles and below the ureter, and terminate in the internal iliac vein. The
lymph vessels end in the internal iliac and the sacral lymph glands.
Prostatic Urethra. The
prostatic part of the urethra is about
SURGICAL CONSIDERATIONS
PROSTATIC ABSCESS This condition follows a
prostatitis and the dense pelvic fascia which invests the may appear as a single
large abscess or as several small foci. The path of least resistance is toward
the urethra, and many prostatic abscesses may rupture here. The dense pelvic
fascia which invests the may appear as a single large abscess or as prostate
usually resists the progress of the
FIG. Perineal prostatectomy. Denonvilliers' fascia has been incised, and
the prostate gland is exposed.
FIG. Retropubic prostatectomy. (A) The approach through the space of
Retzius is indicated by the arrow. (B) Exposure and mobilization of the gland.
(C) Enucleation and removal of the prostate. (D) Appearance after removal of
the gland. (E) Closure.
abscess upward through the peritoneum and into
the pelvic cavity; the strong urogenital diaphragm resists its spread downward
to the perineum. However, it can reach the perineum by pointing toward the
rectum where it comes into contact with a thin rectovesical fascia. The abscess
may follow this fascia through the space between the urogenital diaphragm and
the anus into the perineum; the pus also may erode through the rectovesical
fascia and rupture into the rectum. A periprostatic infection can lie lateral
to the gland, invade the levator ani muscle and reach the ischiorectal fossa. A
rare path of spread is anteriorly through the pubovesical ligaments and into
the space of Retzius.
PROSTATECTOMY Four accepted methods of removal of
the prostate gland have been described: suprapubic prostatectomy, transurethral
resection, perineal prostatectomy and retropubic prostatectomy. The
suprapubic prostatectomy requires exposure through the bladder. There are
many who find fault with this approach because the gland lies entirely outside
of the bladder; the bladder is entered, the enucleation is done blindly and
hemorrhage may be difficult to control. In addition, it does not permit
complete removal of a carcinomatous gland which has invaded the capsule. The
transurethral resection operation is well adapted to smaller glands, median
bars and serves as a palliative procedure for obstruction due to carcinoma.
However, in the hands of excellent resectionists, the scope of the operation is
much greater, and the results are good; hence, some outstanding urologists
remain most enthusiastic about it. The morbidity may be prolonged by the
necrosing of tissue electrically treated; in a fairly large percentage of
resections the procedure has to be repeated. Perineal prostatectomy is a
surgical operation in which the gland is removed under direct vision;
hemorrhage can be controlled more readily. It is applicable in the removal of a
malignant prostate which has invaded the capsule. It requires a thorough
knowledge of perineal anatomy and a highly skilled and trained surgical team.
In inexperienced hands, a persistent fistula may result, the rectum may be
injured or complete incontinence may be an annoying sequela. Retropubic
Prostatectomy. The space of
Retzius has been considered the potential danger area, nevertheless this
operation takes place directly through this space. The skin incision extends
from the symphysis to the umbilicus in the midline, and the rectus muscles are
separated. The preprostatic fat which occupies the space of Retzius is
identified. The bladder is retracted upward, and an incision is made into the
prostatic capsule. The gland is enucleated to the vesicle neck, the prostate is
peeled off of the bladder, and the prostatic arteries are ligated. A catheter
is introduced from the meatus and into the bladder.This operation too has its
antagonists and protagonists. No one operative procedure will meet the
requirements of every case; therefore, all the methods must be known and
included in the armamentaria of the surgeons who do this type of work.
PELVIC VISCERA IN THE FEMALE
Embryology.
Before the sex of the embryo is determined, 4 parallel
tubes grow caudally in the subperitoneal tissue of the posterior abdominal
wall. They are the right and the left miillerian (paramesonephric) ducts and
the right and the left wolffian (mesonephric) ducts. They terminate in that
anterior part of the cloaca known as the urogenital sinus. The wolffian duct
predominates in the male and gives rise to the spermatic duct, the epididymis,
the vas deferens and the ejaculatory duct. The miillerian duct predominates in
the female and becomes the fallopian tubes, the uterus and the vagina. The
cephalic ends of Muller's (paramesonephric) ducts open into the body cavity,
but the caudal ends, having crossed the wolffian ducts, fuse with each other
and form a single tube which opens into the urogenital sinus. The cranial ends
of these ducts become the fallopian tubes; their intermediate parts fuse to
form the uterus, and the caudal ends fuse and form the upper part of the
vagina. To meet its fellow in the midline, the intermediate part of the duct
must pull away from the side wall of the pelvis and in so doing pulls a
peritoneal fold with it; this fold becomes the broad ligament of the uterus.
Therefore, the broad ligament is the "mesentery of the miillerian
duct." In the male, Miiller's duct almost entirely disappears, with the
exception of its caudal extremity, which forms the prostatic utricle, and the
cephalic extremity, which forms the appendix testis (sessile hydatid). The
wolffian duct only persists at its extremities in the female. At its cephalic
end it forms longitudinal tubules of the epoophoron and the paroophoron. The
transverse tubules of these vestigial bodies occupy the broad ligament in the
vicinity of the ovaries. The caudal extremity of the wolffian duct may persist
as a tubular remnant, known as the duct of Gartner, which is embedded in the
lateral wall of the cervix and the vagina. The ovary originally is a
retroperitoneal abdominal organ, as is the testicle, but in
FIG. Development of the female pelvic viscera. (A) Two wolffian and two
miillerian ducts are present. (B) The wolffian ducts do not persist in the
female. (C) The cranial ends of the miillerian ducts become the fallopian
tubes, the intermediate parts fuse to form the uterus, and the caudal ends fuse
and form the upper part of the vagina. In the female, the wolffian duct
persists only at its extremities; at its cephalic end, the epoophoron and the
paroophoron are formed; at its caudal end, the duct of Gartner may persist.
the adult it becomes a pelvic organ. The
gubernaculum of the ovary is attached caudally to the skin, which later becomes
the labium majus; in its course the gubernaculums becomes attached to the side
of the uterus. In the male, the gubernaculum testis passes through the inguinal
canal and into the scrotum, pulling with it a processus vaginalis and the
testis; in the female, the gubernaculums ovarii passes through the inguinal
canal into the labium majus, followed by a similar processus vaginalis which is
called the
the ovary and the round ligament of the uterus.
These 2 ligaments are practically continuous at their site of uterine attachment,
which is just below the uterine tube. The round ligament of the uterus
parallels the subperitoneal course taken by the vas deferens in the male; it
crosses the side wall of the pelvis and the external iliac vessels, then turns
around the inferior epigastric artery, passes through the inguinal canal and
ends in the labium majus, which is the homologue of the scrotum. The ovary may
descend abnormally; in such instances it follows the gubernaculum into the
labium majus; this is known as an ectopic ovary.
THE 6 LIGAMENTOUS SUPPORTS The 6 ligamentous
supports of the female pelvic viscera are the broad, the round, the
uterosacral, Mackenrodt's, the ovarian and the infundibulopelvic ligaments. Broad
Ligaments. Each broad ligament of the uterus is a thick, mesenterylike fold
which passes from the lateral margin of the uterus to the lateral wall of the
pelvis. It is a structure of great importance because of its relation to the
uterine tube, the uterine and the ovarian vessels and the ovary. The 2 layers
of the broad ligament are triangular in shape when placed on a stretch.
Medially, its 2 layers separate to envelope the uterus, and inferiorly and
laterally they separate to cover the floor and the side wall of the pelvis.
Superiorly, these 2 layers become continuous with each other and form a free
upper border, which in the normal pelvis is more anterior than superior. The
inner
FIG. The 6 ligamentous supports of the female pelvic viscera. (A) The
broad, round, ovarian, infundibulopelvic, uterosacral and Mackenrodt's
ligaments are shown from behind. On the right the posterior leaf of the broad
ligament has been removed to show the structure of the ligaments. (B)
Transverse diagrammatic section to show the formation of Mackenrodt's ligament.
four fifths of the free upper border is occupied
by the fallopian tube, and the shorter lateral one fifth extends beyond the
tube from the fimbriated end to the wall of the pelvis as the infundibulopelvic
ligament. The 2 layers pass in opposite directions at their lines of attachment
to the lateral pelvic wall and floor to become continuous with the general
peritoneal lining of the pelvic cavity. Between the layers of the broad
ligament the extraperitoneal connective tissue is located; this is the parametrium.
In addition to the uterine tube, the round ligament of the uterus, the ovarian
ligament, the epoophoron and the uterine and the ovarian vessels also are found
between the two layers of the broad ligament. Two secondary ligaments originate
from it. Passing posteriorly is a fold, the mesovarium, which contains
the ovary and the ovarian ligament. The mesosalpinx is that portion of
the broad ligament which lies immediately below the uterine tube between it and
the ovary.
The round ligaments of
the uterus are not duplications of peritoneum but are true ligamentous
fibromuscular cords. They pass from the superolateral angle of the uterus to
the internal inguinal ring, representing the lower part of the gubernaculum;
they are enclosed between the serous layers of the broad ligaments. Usually
they raise a ridge on the anterior aspect of the broad ligament and
occasionally may be accompanied by a persistent tubular prolongation of
abdominal peritoneum known as the
The infundibulopelvic ligament
(suspensory ligament of the ovary) extends from
the tubal end of the ovary to the lateral pelvic
FIG. Ligamentous supports of the female pelvic viscera. (A) The division
of the gubernaculum into the ovarian and the round ligaments. (B) The
structures seen from above and in front. The anterior leaf of the left broad
ligament has been reflected forward.
wall; it is the lateral one fifth of the broad
ligament and is not occupied by the fallopian tube. It passes upward from the
ovary, crosses the external iliac vessels and becomes lost in the fascia and
the peritoneum covering the psoas major muscle. The ovarian vessels and nerves
travel in this ligament. The uterosacral ligaments are 2 short,
fibromuscular cords which pass backward from the posterior aspect of the upper
end of the cervix on each side of the rectum and end in the sacrum. They lie
directly in contact with the peritoneum and form ridges called recto-uterine
folds in the lateral walls of the recto-uterine pouch. Following inflammatory
conditions, these ligaments may shorten and overaccentuate the antefiexion of
the uterus. The function of the uterosacral ligaments is to hold the cervix up
and back. If they fail to function (congenital weakness, loss of tonus from
pregnancies, etc.), the cervix is displaced downward and forward; this permits
a backward displacement of the corpus so that the axis of the uterus and the
vagina coincide. Intra-abdominal pressure then forces the uterus into the
vagina (prolapse). Mackenrodt's ligaments (cardinal or transverse cervical ligaments)
are situated lateral to the cervix and the vagina and are continuous on
each side with the corresponding uterosacral ligaments. They are the bases of
the broad ligaments. Blood vessels, especially veins, make up the chief
components of this ligament. They are a condensation of parametrial tissue
which helps suspend the cervix and the uterus to the pelvic walls. When the
cardinal ligaments become stretched, the uterus drops to a lower level. The
ovarian ligament is a rounded fibromuscular cord which is enveloped between
the 2 layers of the broad ligament and may be seen through the peritoneum as it
passes along a line separating the mesosalpinx from the mesovarium. It extends
from the uterine (lower) pole of the ovary to the lateral aspect of the uterus;
here it is attached between the fallopian tube and the round ligament of the
uterus. The ovarian and the round ligaments of the uterus together represent
the gubernaculums of the ovary, the entire cord being subdivided into ovarian
and uterine parts.
UTERUS The uterus is a pear-shaped muscular organ
that is intermediate in position between the bladder, the rectum and the broad
ligaments. It is
FIG. The uterus as seen from above.
attached to its side margins, and the ligament of
the ovary and the round ligament of the uterus are attached just below the
tubes. The uterus is divided into three parts: a base or fundus; a main
portion, the body or corpus; and the larger lower prolongation known as the
neck or cervix, which projects into the vagina. The cervix is demarcated from
the corpus by a slight constriction called the isthmus. The fundus and the body
form the upper
FIG. The uterus as seen in sagittal section. The organ is divided into 3
parts: a fundus, a corpus and a cervix.
A fatty fibrous tissue fills the spaces between
the broad ligaments. This tissue is called the parametrium and is most
abundant near the cervix and the vagina, where it becomes continuous with the
extraperitoneal tissue of the pelvic wall and floor. The cervix is the
narrower cylindrical segment of the uterus; it enters the vagina through the
anterior vaginal wall and lies at right angles to it. Since it pierces the
vagina, it is divided into supravaginal and intravaginal (vaginal) portions. The
supravaginal part lies above the ring of vaginal attachment, is covered with
peritoneum posteriorly and is related to the intestines. Anteriorly, it is
separated from the bladder by fatty tissue and is connected laterally with the
broad ligament and the parametrium, which contains the blood vessels. The lower
intravaginal (vaginal) portion is the free segment which projects through the
vault of the vagina; it is covered with mucous membrane which has been
reflected onto it from the upper part of the vaginal wall. The cervix opens
into the vaginal cavity through the external os. The os has anterior and
posterior lips which are normally in contact with the posterior vaginal wall;
this wall ascends to a higher cervical level than does the anterior wall and thus
envelopes the inferior third of the cervix. In nulliparae, the os is a small
transverse slit, the lips of which are smooth and rounded; but in multiparae it
is wider, and the lips are quite irregular. The cavity of the uterus is
small when compared with the thickness of its wall. In sagittal section it is
an elongated narrow cleft, but when viewed from in front is triangular in shape
with all of its sides being convex inward. Its normal capacity is about 3 to 8
cc. The base of the triangle is directed upward, and at its two upper corners
it is continuous with the fallopian tubes; the apex of the triangle is directed
downward where, at the constricted internal os (corresponding to the isthmus
externally), it becomes continuous with the cervical canal. The mucous membrane
of the cavity of the body of the uterus is smooth and velvety. The canal of
the cervix is spindle-shaped and about
FIG. Attachments of the broad ligament.
these folds usually are absent after the first
pregnancy. The body of the uterus is the most movable part; the cervix,
although mobile, is held rather firmly at either side by f ascial and
ligamentous bands known as Mackenrodt's {cardinal) ligaments. In the
virgin the uterus lies with its long axis almost parallel with the superior
aperture of the true pelvis and almost at right angles to the long axis of the
vagina. Therefore, the fundus of the uterus is directed forward; this position
is described as anteversion. Furthermore, the uterus is bent forward upon
itself, producing antefiexion. It also is rotated slightly on its own axis. The
position varies greatly in different individuals and is subject to change,
depending on posture and the condition of the bladder and the rectum. The
structure of the uterus consists of 3 layers: an outer serous coat, a
middle muscular coat and an inner lining, the mucous membrane. The outer
serous coat (perimetrium) is visceral peritoneum which consists of
mesothelial cells; it is attached to the subjacent muscular coat through a thin
layer of connective tissue. This attachment is firm over the fundus and the
posterior part of the corpus but is much less firm over the posterior part of
the cervix. The muscular layer is known as the myometrium and
makes up the greater part of the organ. It consists of interlacing bundles of
smooth muscle fibers which are united by connective tissue. These fibers
increase in size and probably in number during the first half of pregnancy and
they never regain their virginal size. The inner lining of mucous
membrane is the endometrium; it is smooth and velvety and is about 2 to
FIG. The vagina, frontal section. The vagina passes through the fascia
of the pelvis, between the levator ani muscles, through the urogenital
diaphragm and opens onto the surface of the perineum.
Malformations.
Various developmental malformations of the uterus may take place. The 2
miillerian ducts normally fuse over those parts which form the uterus and the
vagina. The upper or tubal portions of the ducts retain their independence as
the 2 fallopian tubes. The fused uterus and the vagina are at first partitioned
by a median septum which disappears later, and the double uterine and vaginal
canals become converted into a single cavity. The disappearance of this median
partition occurs from the vulva upward, and the degree of its absorption may
vary. Therefore, a partitioned vagina with a partitioned uterus (uterus
didelphys), a completely developed single vagina and a partitioned uterus (uterus
duplex), or a single vagina and a single uterus (uterus simplex) may
result. Occasionally, the ducts remain separated throughout their entire length
and then 2 entirely separate uteri and vaginae are found. The uterus may
be divided, producing the bicornate uterus; the cervix may be either
single or double. If one miillerian duct fails to keep pace with the other, any
variety of asymmetry may result.
FIG. The vagina. (A) Seen from in front and above. The arrow leads to
the lateral fornix. (B) The "H"-shape of the upper part of the vagina
seen in cross section.
VAGINA The vagina is a flattened but distensible
musculomembranous canal which usually measures about
UTERINE TUBES (FALLOPIAN TUBES) The uterine tubes
are the paired oviducts which convey the ovum to the uterus. Each is about
FIG. Uterus, ovaries and fallopian tubes. (A) A section of the uterus
has been removed so that the interior of the uterine cavity and the cervical
canal can be seen. (B) Transverse section through the ovary.
Each tube emerges from the uterine wall at the
junction of the corpus and the fundus uteri. Its course is at first
horizontally outward and then backward; it curls around the tubal end of the
ovary and overlaps its medial surface. It connects with the uterine cavity
through the uterine ostium and with the abdominal cavity through the abdominal
ostium. The calibre of the latter is subject to great variation in different
individuals. These 4 chief subdivisions are recognized. (1) The
interstitial part is a short portion which begins at the upper angle of the
uterine cavity with which it connects by a minute ostium. It is that part which
passes through the uterine wall (about ½ inch thick) and appears
externally at the cornu just above the uterine attachment of the round and the
ovarian ligaments. (2) The isthmus is that medial inch of tube which is short
and cordlike; it appears just outside of the uterus and runs a rather narrow
but straight course. The lumen of the isthmus gradually increases and joins the
ampulla. (3) The ampulla is that portion which is the widest and the longest
subdivision of the tube; it appears to be convoluted. It is thinwalled and
dilatable and constitutes the most important part of the tube. It leads into
the trumpet-shaped expansion which is the infundibulum. (4) The infundibulum is
funnelshaped, but the surface of the funnel is broken into numerous fingerlike
processes called fimbriae, which give the free margin a fringed or ragged
appearance. From its uterine attachment to the fimbriated end, the tube is
enveloped by a superior fold of broad ligament, the mesosalpinx. The
isthmus of the tube, which has a relatively short mesosalpinx, moves with the
uterus, but the ampulla and the infundibulum, with a comparatively long
mesosalpinx, are nearly as mobile as the ovary. In addition to an outer serous
coat derived from the broad ligament, the tube is surrounded by a subserous
layer and a muscle layer which is continuous with that of the uterus. The
mucosa lining the tube is peculiar in that it is arranged in folds which are
directed longitudinally. This mucous membrane is covered with a ciliated
epithelium; the action of the cilia is supposed to create a stream of lymph
from the peritoneal cavity into the mouth of the tube and along it to the
uterus. The arterial blood supply is derived from the tubal branches of
the uterine and the ovarian arteries. The lymph vessels drain to the
aortic glands with the vessels to the ovary and the fundus of the uterus. The nerve
supply is derived from the uterine and the ovarian plexuses and ultimately
from 11 and 12 T and
OVARIES The genital gland of the female resembles
a large almond, in both size and shape. It projects from the posterior layer of
the broad ligament, which it draws outward to form the mesovarium. It is
covered with cuboidal epithelium, not peritoneum. The mesovarium is usually
short and attaches only to the anterior border of the ovary. The gland is
smooth and pink in young nulliparae but becomes gray and puckered in elderly
women and in multiparae. This is due to the repeated discharge of ova through
its surface and the resultant formation of puckering scars; in old women it
becomes shrunken, wrinkled and atrophic. The ovary lies in the peritoneal depression
on the side wall of the pelvis; the depression is bounded behind by the ureter
and in front by the broad ligament. In the floor of this fossa the obturator
vessels and nerves are found. At the first pregnancy, the broad ligament
enlarges with the uterus and carries the ovary up into the abdomen proper.
After childbirth, the organ returns to the pelvis but seldom regains its former
position; it may be found in any location in the dorsal part of the pelvis. It
also may be prolapsed deep into the cul-de-sac, where it can be palpated
vaginally, lateral to or behind the cervix. Extremities and Surfaces. The
ovary has 2 extremities and 2 surfaces. The tubal extremity, which is referred
to as the upper pole, is rounded, faces superiorly and is embraced by the
fallopian tube. The infundibulopelvic ligament (suspensory ligament of the
ovary) attaches this pole to the peritoneum of the pelvic wall; it is derived
from the upper and the lateral aspects of the broad ligament and contains the
ovarian vessels. The fimbriae of the fallopian tube also are found at the upper
pole of the organ. The lower (uterine) pole connects the ovary with the
superolateral angle of the uterus by means of the ovarian ligament; it is about
¼ inch above the pelvic floor. The medial surface is directed inward,
and since it is overlapped to a great extent by the fallopian tube, only a
small part of it is exposed to the eye. The lateral surface faces outward and
is in direct contact with the parietal peritoneum of the pelvic wall where this
layer is depressed to form the ovarian fossa. Although pregnancy may alter the
position of the ovary in multiparae, it nevertheless remains anchored at 3
places: the ovarian ligament, the mesovarium and the infundibulopelvic
ligament. Arteries. The blood supply is derived from the ovarian artery,
a direct branch of the aorta, which arises just below the origin of the renal
artery. Unlike the corresponding artery in the male, it does not pass through
the internal inguinal ring but turns medially over the pelvic inlet to enter
the infundibulopelvic ligament of the ovary. Its branches reach the hilum by
way of the mesovarium, but the terminal branches continue medially in the broad
ligament to supply the uterine tube and the upper part of the uterus. It anastomoses
with branches of the uterine artery. Veins. Several veins arise from the
hilum of the ovary but they unite to form a single or double ovarian vein. The
right ovarian vein empties into the inferior vena cava, and the left joins the
left renal vein. Lymphatics. The lymph vessels follow the ovarian veins
and end in the aortic lymph glands. Nerves.
The nerve supply is derived from the aortic and the renal plexuses.
The structure of
the ovary reveals 2 zones: a central medullary and an outer cortical layer or
zone. The medullary zone is characterized by its numerous blood vessels within
the connective tissue. The cortical layer, besides containing connective
tissue, contains the essential glandular tissue in the form of graafian
follicles in various stages of development.
URETERS
The ureters are expansile muscular tubes, a
whitish in appearance which are approximately
FIG. The ureter. (A) The ureters are shown in their entire courses and
their anatomic relationships. Four vessels cross the right ureter: the right
colic, the testicular (ovarian), the ileocolic and the superior mesenteric. (B)
The relation of the left ureter to the intersigmoid fossa.
RELATIONS From above downward the ureter rests on
the genitofemoral (genitocrural) nerve, the common iliac vessels on the left
side, and the external iliac vessels on the right side; after passing downward
on the internal iliac artery, it is related to the ligaments in the pelvis. As
the ureter bends into the true pelvis the ovarian (testicular) vessels
gradually diverge from it. The end of the abdominal portion of the ureter is
separated from the iliopectineal line by the psoas muscle and the iliac
vessels. On the right side it crosses the vessels at the point of bifurcation
of the common iliac artery, but on the left side it crosses the common iliac
about 1 to
RIGHT URETER The right ureter is a little
lateral to the inferior vena cava; its pelvis is covered by the second part of
the duodenum. Four sets of blood vessels cross in front of it, between it and
the peritoneum. These are: the right colic artery, the testicular
FIG. The 3 parts of the pelvic ureter. (A) It is convenient to divide
the pelvic portion of the ureter into 3 parts: (1) a posterior part in the
uterosacral ligament, (2) an intermediate part, Mackenrodt's ligament, and (3)
an anterior part in the vesico-uterine ligament. (B) The intermediate part of
the ureter is surrounded on all sides by vessels, mostly veins. (C) The uterine
artery is lateral to the first part, passes across the second part and is
medial to the third part of the ureter.
(ovarian) artery, the ileocolic artery and the
superior mesenteric artery in the root of the mesentery.
LEFT URETER The left ureter is a little
lateral to the inferior mesenteric vein. Its pelvis is more exposed than the
right and, after appearing from behind the renal vessels, is covered only by
the peritoneum. It is separated, as on the right side, at intervals from the
peritoneum by the upper left colic, the testicular (ovarian) and two or more
left colic vessels. Because of the vessels which cross the abdominal part of
the ureter, the extraperitoneal lumbo-inguinal approach is preferable to the
transperitoneal one.
THE PELVIC PART OF THE URETER This part is
divided into 3 portions: (1) a pars posterior (in the uterosacral ligament),
(2) a pars intermedia (in Mackenrodt's ligament) and (3) a pars anterior (in
the vesico-uterine ligament). The pars posterior of the pelvic portion
of the ureter begins at the level of the sacroiliae joint. At this point the
ureters are separated by a distance of 6 to
THE PELVIC PART OF THE URETER IN THE MALE This
part of the ureter crosses the beginning of the external iliac artery, passes
backward and downward along the lower border of the internal iliac
(hypogastric) artery and reaches the level of the ischial spine. At this point
it curves forward and mediad in the fat above the levator ani muscle and
reaches the posterosuperior angle of the bladder. It passes through the
posterior wall of the bladder at an extreme oblique angle, running medially and
downward. It opens into the bladder at the upper angle of an area called the
trigone. As the ureter approaches the bladder, it is under cover of the closely
adherent peritoneum and at times may be seen shining through it. In the
beginning of its course the internal iliac artery is above and behind it.
Lateral to it are the psoas and the obturator internus muscles, the external
iliac vein, the obturator nerve, the umbilical artery, and the obturator and
the inferior vesical vessels. As the ureter turns downward it lies in the fat
above the levator ani muscle and beneath the peritoneum; the vas deferens
crosses above it, between it and the peritoneum near the bladder. Near the
bladder it is surrounded by a plexus of veins and is overlapped by the upper
end of the seminal vesicle. It receives its blood supply from branches arising
from the renal, the testicular, the colic, the vesical and the middle rectal
arteries. Because of its great vascularity, the ureter may withstand a
considerable amount of surgical trauma, and large segments of it may be
mobilized without sloughing. It is for this reason that injury to it heals
quickly. Its nerve supply is derived from the renal, the testicular and the
hypogastric plexuses. The lymphatics end in glands nearest it in the abdomen
and the pelvis. The ureter is constricted in certain localities. The uppermost
of these constrictions is about
FIG. The ureter. (A) The blood supply of the ureter is derived from the
renal, the testicular, the colic, the vesical and the middle rectal arteries.
(B) The pelvic portion of the ureter, showing its entrance into the bladder.
FIG. The ureter in the male, seen from the right. The vas deferens
crosses above the ureter as it is overlapped by the upper end of the seminal
vesicle.
SURGICAL CONSIDERATIONS
EXPOSURE OF THE URETER It may be necessary to
expose the ureter for excision, the removal of stones or for repair. A number
of incisions have been described; however, it is agreed that this structure is
approached most readily by a retroperitoneal route. The incision should be
ample and allow for examination of not only the entire ureter but the kidney as
well. The patient is placed in the lateral decubitus and is well arched over a
kidney-rest or a sandbag. An adequate lumbo-iliac incision is made. The
incision begins about the middle of the 12th rib and extends downward and
forward to a midpoint between the center of the iliac crest and the anterior
superior iliac spine; it then passes around the anterior iliac spine and
continues forward and parallel with the inguinal ligament. The external and the
internal oblique muscles and the transversus abdominis muscle are incised in
the direction of the skin incision; the transversalis fascia is incised; and
the extraperitoneal fat is exposed. The peritoneum is mobilized medially, and
the ureter and the pelvic vessels are identified. The ureter normally remains
adherent to the peritoneum when that structure is reflected toward the midline.
Nevertheless, the ureter can be detached easily from the peritoneum to permit
any surgical procedure or exploration which might be deemed necessary.
FIG. Exposure of the right ureter. The illustration reveals a
retroperitoneal approach. The peritoneum is retracted medially, and the
relations to the surrounding vessels are demonstrated.
NEUROVASCULAR STRUCTURES
Most of the vessels supplying the structures
within the pelvis lie in the extraperitoneal fatty tissue which intervenes
between the peritoneum and the fascia. The nerves, at first, lie outside of the
fascia and are not only retroperitoneal but, like the muscles, are also
retrofascial.
ARTERIES The arteries of the pelvis are the
internal iliac (hypogastric), the superior hemorrhoidal (rectal), which is the
continuation of the inferior mesenteric, and the median sacral. The ovarian
artery is an exception in that it does not arise within the true pelvis but
originates from the aorta at the level of the kidneys.
The internal iliac artery
(hypogastric) is the largest artery in the true pelvis and
gives rise to all the arteries of the pelvis except the superior hemorrhoidal,
the median sacral and the ovarian. It is a wide vessel, smaller than the
external iliac, and is about 1 ½ inches long. It arises as a terminal
branch of the common iliac on the medial border of the psoas muscle, passes
backward and downward across the medial surface of the psoas muscle and enters
the pelvis. In its course it passes the sacro-iliac joint and ends near the
upper border of the greater sciatic notch by breaking up into anterior and
posterior divisions which supply the exterior and the interior of the pelvis.
Although it is narrower in the adult than the external iliac, it is twice as
wide in the fetus because of its umbilical branch which passes to the umbilicus
and the placenta. After birth, the umbilical branch is patent to a point where
the superior vesical arteries arise, and beyond this it becomes a fibrous cord
called the lateral umbilical ligament. The ureter is in front of it; behind it
lies its vein, and as it descends subperitoneally it crosses medial to the
external iliac vein and the obturator nerve. At the upper border of the greater
foramen, the artery divides into anterior and posterior divisions; the terminal
branches from these divisions follow a pattern which is open to considerable
variation. The posterior division gives rise to the following 3
branches, all of which are parietal: the iliolumbar, the lateral sacral and the
superior gluteal.
The iliolumbar artery, located
at the 5th lumbar segment, corresponds to a lumbar artery. It passes
upward and laterally, first between the obturator nerve and the lumbosacral
cord and, secondly, between the psoas muscle and the spinal column. Opposite
the pelvic brim the artery divides into an iliac and a lumbar branch, the
former ramifying the iliac fossa and the latter ascending behind the psoas to
send a spinal branch into the vertebral canal via the lumbosacral
intervertebral foramen. The iliolumbar vein does not descend into the pelvis
with its artery but ends in back of the common iliac vein.
The lateral sacral artery passes
mediad and downward in front of the sacral nerves, and each of them divides
into 2. Therefore, 4 arteries pass through the anterior sacral foramina to
nourish the structures in the sacral canal; they emerge through the posterior
sacral foramina to supply the muscles on the back of the sacrum and the
overlying skin.
The superior gluteal artery is
the largest branch of the posterior division of the internal iliac artery, and
its course in the pelvis is short. It passes downward and backward between the
lumbosacral trunk and the 1st sacral nerve, pierces the parietal
pelvic fascia and enters the gluteal region via the upper part of the greater
sciatic foramen above the piriformis muscle. It travels with its vein and the
superior gluteal nerve. The anterior division of the internal iliac
artery gives rise to 9 branches. All of the posterior branches previously
described are parietal, but the anterior branches are both visceral and
parietal. The 3 parietal branches are the obturator, the internal pudendal and
the inferior gluteal; the 6 visceral branches are the umbilical, the superior
vesical, the inferior vesical, the middle hemorrhoidal, the uterine and the
vaginal.
The obturator artery passes
forward and downward along the lateral wall of the pelvis and emerges through
the obturator foramen above the obturator internus muscle. It is accompanied by
its nerve and vein; the order, from above downward, is nerve, artery and vein.
Converging on the nerve and after passing through the upper part of the
obturator foramen, it divides into lateral and medial branches which surround
the obturator foramen lying between it and the obturator externus muscle. These
branches encircle the outer surface of the obturator membrane, supply the
obturator externus muscle and give an acetabulator branch to the hip joint. An abnormal
obturator artery, when present, is important in the surgery of femoral
hernias. The obturator and the inferior epigastric arteries each supply
FIG. The right internal iliac artery and its branches. The uterus and
the rectum have been pulled to the left and forward.
pubic branches, which are small and anastomose at
the back of the pubis. In 30 to 35 per cent of cases, however, the pubic branch
of the inferior epigastric artery is large and replaces the obturator branch;
it is called the abnormal obturator artery. This apparently is attributable to
an obliteration of the usual origin of the obturator artery. From its origin
the abnormal artery descends into the true pelvis on the medial side of the
external iliac vein and usually lies lateral to the femoral ring. If the artery
is on the medial side of the ring and along the edge of the lacunar ligament,
it is in a precarious location, since cutting this ligament in a strangulated
femoral hernia might sever the artery and result in profuse hemorrhage.
The internal pudendal artery travels
a rather complicated course. It descends over the piriformis muscle and the
sacral plexus in the interval between the piriformis and the coccygeus muscles.
At this point the artery leaves the pelvis through the greater sciatic foramen
and enters the buttock, where it rests on the spine of the ischium with the
pudendal nerve on its medial side and the nerve to the obturator internus on
its lateral side; these are covered by the gluteus maximus muscle. The artery
then disappears through the lesser sciatic foramen and reaches Alcock's
pudendal canal where it passes downward to gain access to the peri-
FIG. The right internal iliac artery. (A) Relations of the prostate and
bladder. (B) The middle hemorrhoidal vessels form the posterior boundary of the
prevesieal space.
FIG. The obturator arteries: (A) normal; (B) abnormal.
neum. It terminates by piercing the perineal
membrane and divides into the deep and the dorsal arteries of the penis or the
clitoris. It supplies inferior rectal, scrotal (labial), transverse perineal,
bulbar, penile and clitoral branches.
The inferior gluteal artery is
the terminal and largest branch of the anterior division. It passes downward
and backward, pierces the fascia in front of the piriformis muscle and
continues between the 1st and the 2nd, or the 2nd and the 3rd sacral nerves. It
leaves the pelvis through the lower part of the greater sciatic foramen and
appears in the buttock between the piriformis and the gemellus superior. Its
branches in the pelvis are only twigs to the surrounding structures.
The umbilical artery passes
downward and forward along the side wall of the pelvis in front of the
obturator nerve; it is in contact with the bladder when it is full but is some
distance from it when it is empty. It proceeds upward from the bladder to the
umbilicus, being covered by peritoneum. In the pelvis it is crossed by the
ureter and the vas deferens (ligamentum teres in the female). It gives off the
superior vesical artery; beyond that point its lumen becomes obliterated, and
then it is known as the lateral umbilical ligament. Under that name it ascends
out of the pelvis in the extraperitoneal tissue of the anterior abdominal wall
to reach the umbilicus. The umbilical artery has no accompanying vein; the
umbilical vein which accompanies the fetal arteries in the umbilical cord
leaves them at the umbilicus, continues to the liver and becomes the round
ligament of the liver.
The superior vesical arteries may
arise as 2 or 3 branches from the umbilical artery. They supply the superior
aspect of the bladder and may give off the artery to the vas deferens.
The inferior vesical artery is
small; in the male it arises a little below the obturator artery. It passes
forward to reach the bladder and supplies the seminal vesicles, the prostate
and the posterior and the inferior parts of the bladder. It gives off a long
slender branch called the artery of the vas deferens which supplies and
accompanies the vas as far as the testis.
The vaginal artery replaces
the inferior vesical artery of the male. It is larger than the latter and
arises a little below the obturator artery, descends and divides into branches
which pass to the vagina; other branches pass onward to the posterior and the
lower parts of the bladder. The middle hemorrhoidal (rectal) artery travels in
a leash of veins that forms the posterior limit of the retropubic space. It
usually arises from the internal pudendal artery but may arise with the
inferior vesical. It passes medially to the rectum, ramifies its walls and
sends twigs forward to the vagina or to the seminal vesicles and the prostate
gland. With the veins and a condensation of extraperitoneal areolar tissue, it
constitutes the rectal stalk or the lateral rectal ligament. The uterine artery
is a large vessel which arises near the lower end of the anterior division of
the internal iliac. It may be divided conveniently into the following parts:
(1) descending, (2) horizontal and (3) ascending. The descending part
represents its course on the lateral pelvic wall which corresponds to the
posterior edge of the ovarian fossa. Since this part is associated with the
parietal
FIG. The uterine artery. This vessel may be divided into 3 parts: (1)
descending, (2) horizontal and (3) ascending. The tubes and the ovaries have
been retracted outward to show the entire course of the uterine and the ovarian
arteries.
wall, it is known as the parietal portion, and it
is here that the artery may best be isolated from its surrounding tissues. The
horizontal part is the parametrial portion; it crosses the ureter and is
related to Mackenrodt's ligament. This part may be subdivided into
ureterolateral and ureteromesial portions, depending on its relation to the
ureter. The ascending part is the para-uterine portion; it extends upward along
the edge of the uterus and with the accompanying veins it forms a definite
vascular cord in the parametrium. The first branch of the uterine artery is the
ureteral branch which is given off where the artery crosses the ureter; it
passes upward along the ureter. At or just after crossing the ureter, a second
uterine branch, the cervicovaginal artery, is given off. This branch supplies
the posterior and the anterior walls of the cervix and the vagina; it lies
within the cervical and the vaginal septa of the surrounding connective tissue.
The uterine branches proper are given off from part three (ascending part). At
the tubo-uterine junction the uterine artery divides into its 4 terminal
branches: (1) The fundic branches, which pass medially, penetrate the
musculature of the uterus and supply the fundus. (2) The branch to the round
ligament is the smallest branch; it passes forward beneath the tube at the
cornu and accompanies the round ligament along its course in the inguinal
canal. This vessel anastomoses with a branch from the inferior epigastric. (3)
The tubal branch extends from the ligament of the ovary into the mesosalpinx
and divides into cranial and caudal branches. The cranial branch extends along
the underside of the tube within the mesosalpinx and supplies branches to both
the tube and the ampulla. The caudal branch lies in the lower portion of the
mesosalpinx near the hilus of the ovary and bends around the upper extremity of
the ovary to reach the infundibulopelvic ligament where it anastomoses with the
ovarian artery. The cranial and the caudal branches anastomose via small
vessels which cross between the layers of the broad ligament. (4) The ovarian
branch arises beneath the ligament of the ovary, extends along the ventral side
of the ligament, passes to the hilus of the ovary, gives off numerous branches
and then joins the ovarian artery. The location of the uterine artery is
important because of the great number of surgical procedures performed in this
region. It is especially important where it crosses the
FIG. The veins of the pelvis. These veins anastomose freely and form
many venous plexuses on and in the walls of the pelvic viscera.
ureter. This crossing is near the level of the
internal os about 1 or
The ovarian artery is
homologous to the internal spermatic artery in the male. It arises from the
aorta below the origin of the renal artery and passes downward and laterally on
the posterior abdominal wall. Unlike the corresponding artery in the male, it
does not pass to the deep inguinal ring but turns medially over the pelvic
inlet, coursing over the psoas muscle and crossing the external iliac vessels.
It enters the infundibulopelvic ligament and reaches the ovarian hilus by way
of the mesovarium. Its terminal branches continue medially in the broad
ligament and supply the tube and the upper part of the uterus. It anastomoses
freely with branches of the uterine artery. This vessel also crosses the ureter
but in a different direction than the uterine artery. It crosses at an acute
angle at the entrance of the true pelvis where it lies in front of the ureter;
distal to this point the ovarian artery and the ureter separate. The vessel
proceeds along the lateral border of the ureter until the latter dips into the
true pelvis at the terminal line.
VEINS The chief veins of the pelvis are the 2
internal iliac veins and their tributaries. Besides these there are the
superior hemorrhoidal (rectal) and the median sacral veins, and in the female
there is a pair of ovarian pampiniform plexuses. The veins of the pelvis are
thin-walled, accompany the arteries and anastomose freely, thus forming many
venous plexuses on and in the walls of the viscera from which the visceral
veins arise. These plexuses are the rectal, the vesical, the prostatic, the
uterine and the vaginal. They are not closed systems, but since they anastomose
freely, the plexus of one organ communicates with the plexus of a neighboring
viscus. It has been stated that the pelvic viscera lie within a basket woven of
large, thin-walled, venous plexuses among which the arteries thread their way.
Internal Iliac Veins. This
is the widest vein of the pelvis. It is short and is formed by the confluence
of the venae comitantes of the superior gluteal artery and most of the veins
that accompany the other branches of the internal iliac artery. It commences immediately
above the greater sciatic foramen, passes forward and slightly upward out of
the pelvis and ends on the medial surface of the psoas muscle. It joins the
external iliac vein to form the common iliac vein. The internal iliac artery is
below and in front of it, and the sacro-iliac joint and the lumbosacral trunks
are above and behind it; medially, it is separated from the intestines by
peritoneum, and laterally it is related first to the pelvic wall and the
obturator nerve and then to the psoas muscle.
Uterine Plexus. The
veins of the uterus constitute one of the most important of the plexuses. The
uterine plexus completely encircles the ascending portion of the artery and
continues downward along the sides of the vagina as far as the external genitalia.
The uterovaginal plexus lies enclosed in the compact connective tissue of the
cervical and the vaginal septa as it continues upward to the edge of the
uterus. These veins, like the vaginal, are chiefly on the sides of the organ
where they surround the nutrient arteries. They arise in the cavernous venous
spaces in the uterine wall and leave the lateral aspect of the organ at about
the level of the cervix; here, they form a plexus which surrounds the ureter.
The uterine veins anastomose with those of the vagina to form the uterovaginal
plexus. The trunks from this plexus converge into the internal iliac vein or
into one of its main tributaries. The vaginal venous plexus is massed at the
sides of the vagina and communicates with the vesical, the rectal and the
uterine plexuses. A vaginal vein arises on each side and accompanies the
vaginal artery to the internal iliac vein.
Vesical Venous Plexus. In
the female the vesical venous plexus lies on the surface of the bladder; it is
densest around the neck and the upper part of the urethra, where it receives
the dorsal vein of the clitoris. It drains into the vaginal plexus. In the male
the plexus lies on the surface of the bladder, chiefly below, behind and around
the seminal vesicles. It empties into the internal iliac vein by large vesical
veins that accompany the inferior vesical artery.
Prostatic Venous Plexus. This
dense network lies on the front and the sides of the prostate between its
capsule and its fascial sheath. Anteriorly, it receives the deep dorsal vein of
the penis; superiorly, it is continuous with the vesical plexus, into which its
blood is drained. The rectal venous plexuses have been discussed elsewhere.
Ovarian Vein. This
vein arises at the pelvic brim from the pampiniform plexus, which surrounds the
ovarian artery in the pelvis. It accompanies this artery in the abdomen and
ends, on the left side, in the left renal vein; on the right side it passes
directly into the inferior vena cava.
Testicular Vein. In the
male this vein arises from the pampiniform plexus at or near the deep inguinal
ring and accompanies the artery into the abdomen. The left testicular vein ends
in the left renal vein, and the right ends in the inferior vena cava a little
below the level of the renal vein. Many believe that this arrangement of the
left testicular vein predisposes this side to the formation of varicoceles.
Medial Sacral Vein. This
vein is formed from the junction of the venae comitantes which travel with the
median sacral artery. It usually passes along the right side of the artery and
ends in the left common iliac vein.
Inferior Vena Cava. This
vessel is formed by the junction of the 2 common iliac veins on the right side
of the 5th lumbar vertebra. It ascends along the right side of the abdominal
aorta and continues upward in a groove on the posterior surface of the liver.
It perforates the diaphragm between the right and the median portions of its
central tendon. After inclining forward and mediad for about
FIG. The inferior vena cava.
Numerous other connections of these venous
channels have been recorded. So-called "absence" of the vena cava has
been reported. Of course, this refers to the hepatic portion of the inferior
vena cava. The infrarenal or the suprahepatic portions apparently are never
absent. Cases of so-called absence of the hepatic portion of the vena cava have
been reported by Kaestner, Dwight and Neuberger. Other authors such as Huseby
and Boyden and Effler, Greer and Sifers have reported quite extensively on the
subject and can be referred to.
LYMPHATICS The lymph glands and the lymph
vessels of the female pelvis occupy rather constant positions. The afferent
lymph vessels from the skin and the subcutaneous tissue of the perineum, with
the superficial afferent vessels from the inferior extremity, drain into a
small group of lymph glands which are situated on either side of the upper part
of the great saphenous vein. This group is known as the superficial
subinguinal glands. An adjacent group of glands, the superficial
inguinal glands, about 10 to
FIG. The lymphatic system of the female pelvis.
iliac, the internal iliac (hypogastric) and the
common iliac. All of these connect by numerous anastomoses. Their efferent
vessels pass upward to a group of lumbar glands which, because of their
position in relation to the abdominal aorta, are called the preaortic, the
retro-aortic and the lateral aortic glands. The efferent vessels of these
glands end in the cysterna chyli of the thoracic duct opposite the 2nd lumbar
vertebra. Lymph Vessels. The lymph vessels of the pelvic organs end
mainly in the hypogastric and the iliac glands, but a small number may travel
to the aortic, and a few may reach the inguinal glands. Those from the bladder
pass to the external iliac, the hypogastric and the common iliac glands,
and those from the urethra and the intrapelvic part of the ureter drain
directly into the hypogastric group. The efferent lymph vessels from the cervix
and the major portion of the vagina drain with those of the urinary
bladder into the 3 groups of pelvic glands. However, those from the lowermost
part of the vagina descend to join
FIG. Numerous collateral venous channels are available when the inferior
vena cava becomes obstructed; this illustration depicts some of these
possibilities.
FIG. Ligation of the inferior vena cava.
those of the vulva and pass to the superficial
inguinal group. The majority of the lymph vessels from the fundus and the
cervix of the uterus pass laterad in the broad ligament and become
continuous with the ovarian lymph vessels which ascend, with the ovarian blood
vessels, to the aortic glands. However, some of these may pass to the
hypogastric and the other iliac groups. The efferent vessels of the fallopian
tubes join those of the uterus and the ovaries. The vessels from the rectum
pass upward to glands of the sigmoid mesocolon and then to the aortic
group. Those from the anal canal end in the hypogastric glands, and
those from the anus pass forward with those of the perineum to the inguinal
group. Malignant neoplasms of the female genital tract drain into the iliac and
the aortic glands and therefore are not palpable superficially; cancerous
processes which affect the vulva, the perineum, the anus and the lowermost
portions of the vagina may cause easily felt enlargements of the superficial
inguinal glands. However, there is a rare exception to this rule, since lymph
drainage from the fundus of the uterus may travel along the lymphatics of the
round ligament through the inguinal ring and to the superficial inguinal
glands. Since the surgery of cancer is the surgery of the lymph drainage, it is
important to visualize this system when attempting to do a radical removal of
cancer and its extensions.
SURGICAL CONSIDERATIONS
LIGATION OF THE INFERIOR VENA CAVA Ligation or
obstruction of the inferior vena cava can be understood only if one has a
picture of the numerous collateral venous channels that are available when this
structure becomes obstructed. Although the collateral channels are numerous,
these may not be sufficiently developed to allow survival following sudden and
total obstruction of the vessel at or above the level of the renal veins. In
contrast with this, sudden and total ligation of this vessel below the level of
the renal veins is compatible with life. The degree of morbidity and disability
following this differs according to various authors. The operation has been
performed to prevent pulmonary emboli. The chief superficial channel for
collateral circulation is from the femoral vein through the superficial
epigastric and then via the thoracoepigastric vein to the lateral thoracic or
some other tributary of the axillary vein. Other available channels from the
femoral to the subclavian vein are by way of the inferior and the superior
epigastrics, between the circumflex iliac and the lumbar veins, between the
hypogastric and the inferior mesenteric veins, as well as numerous lumbar and
vertebral venous plexuses. The ascending lumbar veins communicate below with
the common iliac vein, with the lateral sacral veins, with the middle sacral
vein when it is present, and with the hypogastric and the iliolumbar veins; in
the abdomen they connect with lumbar and vertebral plexuses, especially at the
level of the renal veins or with the left renal vein itself, and above with the
azygos and the hemiazygos systems. Naturally, the availability of these
pathways varies according to their variational anatomy. Numerous other channels
have been described. For further study one may refer to the works of Northway
and Buxton and of Keen. The inferior vena cava may be approached and ligated
either transperitoneally or extraperitoneally. The transperitoneal operation
is accomplished through a long lower right rectus incision which extends
from the symphysis to well above the umbilicus. The peritoneal reflection is
incised along the paracolic gutter of the cecum and the ascending colon, which
are reflected medially to the midline. The right ureter and the right ovarian
vessels are identified. It is best to ligate the right ovarian veins and
artery. The vena cava is identified easily and is doubly ligated about the
level of the 4th lumbar vertebra. The cecum and the ascending colon are
replaced into their normal positions, and peritonization is accomplished. The
extraperitoneal approach may be accomplished through a lateral incision
similar to that used in lumbar sympathectomy. The inferior vena cava is
identified easily; great caution should be used when ligating this vessel
because of possible injury to lumbar veins. These latter veins are
LlGATION OF THE ILIAC VESSELS Ligation of the
Common Iliac Artery. The indications for this operation are injury,
aneurysms of the external iliac artery, or preliminary to amputations about the
hip joint. The collateral circulation takes place in the following ways: 1.
The inferior mesenteric artery above anastomoses with the visceral branches of
the internal iliac artery below. 2. The ovarian artery above anastomoses with
the uterine and the vesical arteries below. 3. The middle sacral artery above
anastomoses with the lateral sacral branch of the internal iliac artery below.
4. The internal mammary, the lower intercostal and the lumbar arteries above
anastomose with the inferior epigastric below. The operation may be done either
intraperitoneally or extraperitoneally. The intraperitoneal method is
done with the patient in the high Trendelenburg position. A low rectus incision
is used. The bowel is packed off and retracted so that the posterior parietal
peritoneum is exposed and opened over the artery. The veins lie behind the
artery on the right side, but behind and medial on the left. The vessel is
doubly ligated, and at times severed; the peritoneum is sutured. The
extraperitoneal method usually is done through an incision about
FIG. The extraperitoneal approach to the common iliac artery. (A) The
incision extends from the 11th rib to
FIG. The superior hypogastric plexus (presacral nerve).
FIG. The sacral plexus: (A) seen from in front; (B) seen from behind;
(C) relations to musculature.
border of the psoas major muscle is used as the
chief muscular guide. Ligation of the Internal Iliac (Hypogastric) Artery. This
is done for malignant growths in the pelvis which produce hemorrhage, for
gluteal aneurysm and at times for excision of the rectum. The collateral
circulation is carried out in the following way: 1. Communication between the 2
internal iliac arteries. 2. Communications between the internal iliac artery
and the inferior mesenteric. The ureter lies anterior, the vein behind, and the
lumbosacral trunk still more posterior. The operation is similar to the one
described for ligation of the common iliac artery.
Ligation of the External Iliac
Artery. The indications
for this operation are usually femoral aneurysm, and hemorrhage from the
femoral artery or its branches. The collateral circulation takes place in the
following way: 1. Branches of the internal iliac artery above anastomose with branches
of the external iliac artery below. 2. Arteries of the anterior abdominal wall
above anastomose with branches of the inferior epigastric artery below; the
femoral, the superficial epigastric, the circumflex iliac and the external
pudendal vessels also anastomose with the anterior abdominal wall vessels
above. This operation may be done either through a transperitoneal or an
extraperitoneal route. The transperitoneal operation is conducted
through a vertical low rectus incision with the patient in high Trendelenburg
position. The intestines are packed off, and the peritoneum overlying the
vessel is incised; the ligature is passed preferably from within outward so
that the ureter which crosses the artery near its origin can be avoided. The
vein is located to the medial side of the artery. On the left side, the
mesocolon overlies the artery. The extraperitoneal operation is done
through a similar incision described above for exposure of the common or the
internal iliac artery. When the peritoneum is reached, it is wiped medially
until the artery is exposed. The femoral nerve lies lateral, the external
spermatic branch of the genitofemoral nerve anterior, and the vein posterior to
the artery above but medial to it below.
NERVES
LUMBAR SYMPATHETIC CHAIN After a rather thorough
study of the anatomy of the lumbar sympathetics, Yaeger and Cowley have come to
the conclusion that this chain is the most variable portion of the entire
sympathetic system and one of the most variable structures in the human body.
With this in mind, one should not look upon the lumbar sympathetic chain as it
is usually presented in diagrams, namely, as a ganglion resting on the body of
each of the first 4 lumbar vertebrae on the right and the left sides. In 1937,
SURGICAL CONSIDERATIONS
LUMBAR SYMPATHETIC BLOCK This procedure has
become quite popular in the treatment of thrombo-embolic phenomena of the
inferior extremities. Oschner and DeBakey have done much to popularize and
standardize it. The procedure may be performed either in the lateral decubitus
or with the patient in the prone position. Intracutaneous wheals are made
approximately 2 fingersbreadth lateral to the spinous processesof the 1st, the
2nd, the 3rd and the 4th lumbar vertebrae. A needle is inserted
vertically through each wheal until it reaches the transverse process of the
corresponding vertebra. Then the direction of the needle is changed, either
superiorly or inferiorly and toward the midline. The needle can be advanced
another 2 fingersbreadth so that its point comes to lie against the lateral surface
of the body of the vertebra in the retroperitoneal space. Usually 1 per cent
procaine solution is injected. LUMBAR SYMPATHECTOMY This operation has been
recommended for vasospastic conditions of the lower extremities, for megacolon,
hyperhidrosis and chronic ulcers; it may be done either extraperitoneally or
transperitoneally. The retroperitoneal approach can be accomplished
through one of many skin incisions. A commonly used incision begins at the
lower border of the 12th rib at the outer edge of the sacrospinalis group of
muscles and extends downward parallel with the muscles to the crest of the
ilium. It then curves forward along the brim of the pelvis for about 5 or
PRESACRAL (SUPERIOR HYPOGASTRIC) NEURECTOMY This
operation has been done for intractable pain in the uterus, the bladder or the
FIG. Lumbar sympathectomy (retroperitoneal approach). (A) The incision
extends from the 12th rib to the brim of the pelvis. (B) The peritoneum has
been retracted forward, and the lumbar sympathetic chain is found in a gutter
formed by the psoas muscle and the lumbar vertebrae.
rectum, and for the relief of spasms of the
bladder resulting from spinal cord disease or injury. Removal of the presacral
nerves usually causes the loss of power of ejaculation, but the powers of
erection and orgasm is not impaired. The operation is done through a low rectos
incision. The intestines are packed upward, and the bifurcation of the aorta is
sought. The posterior peritoneum is incised above the aortic bifurcation, and
the peritoneal margins are carefully dissected laterally and retracted. The
superior hemorrhoidal vessels (inferior mesenteric), if visible, usually are
retracted to the left, and the presacral nerves are exposed
FIG. Lumbar sympathectomy (transperitoneal approach). (A) Exposure
through a low rectus incision. (B) Incision into the posterior parietal
peritoneum lateral to the inferior vena cava for exposure of the right lumbar
sympathetic chain. (C) Incision into the posterior parietal peritoneum placed
lateral to the sigmoid for exposure of the left lumbar sympathetic chain.
where they lie in the loose connective tissue in
this area. The hollow of the sacrum, between the common iliac arteries, lodges
the continuation of these nerves. At times it may be necessary to ligate the
middle sacral artery. The left common iliac vein lies medial to the artery and
should be protected during this entire procedure; as a rule, the right ureter
is exposed. The nerves are picked up as they cross the aortic bifurcation and
are freed downward. The communicating rami are severed, and the entire plexus
is removed. All primary fibers should be severed. The peritoneal incision is
closed, and the operation is concluded.
PELVIC (SIGMOID) COLON The external iliac artery
can be considered as the dividing line between the iliac and the pelvic colons,
the latter commencing in front of the artery about
FIG. The rectum and
its peritoneal relations: (A) sagittal section of rectal relations in the male,
(B) sagittal section of rectal relations in the female.
sacral vertebra. At the apex of this
"V" there is a small peritoneal recess, the opening of which looks
downward; it is known as the intersigmoid recess (fossa intersigmoidea). It may
be deep or merely represented by a dimple; it acts as a guide to the left ureter.
If a finger is placed in this fossa, the ureter can be rolled on the underlying
common iliac artery; if the peritoneum over it is divided, the left ureter is
exposed. Internal herniations with strangulations of small bowel may take place
into this fossa.
FIG. Anterior and posterior relations of the rectum: (A) seen from above
and in front; (B) seen from behind; part of the sacrum and the coccyx have been
removed.
The superior hemorrhoidal artery runs downward
and medially to the rectum in the medial limb of the pelvic mesocolon. The
length of the mesocolon determines the length, the location and the mobility of
the pelvic colon proper; therefore, there is a wide variation. Usually, the
pelvic colon is situated partly in the abdomen and partly in the pelvis.
However, if the mesocolon is long, it may cross past the midline and appear in
the right lower abdominal quadrant; it may be exposed in the course of an
appendectomy. Such a mobile pelvic colon may twist upon itself, producing a
volvulus. The mesosigmoid
membrane is a thickening and a shortening of the peritoneum of the left
iliac fossa; it binds the junction of the iliac and the pelvic colons to the
pelvic brim. This band has been referred to as Lane's first and last kink. The
reason for this is that Lane thought this band was the first to appear but
involved the last part of bowel. If present, it must be cut when this portion
of the colon is to be mobilized; it is avascular.
RECTUM The rectum begins at the point where the
colon ceases to have a mesentery; this usually occurs in front of the 3rd
sacral vertebra. It not only loses its mesentery but also differs from the
colon in that it is not sacculated, has no taeniae coli or appendices
epiploicae. Its upper third is covered anteriorly and at the sides by
peritoneum; the middle third is covered only anteriorly by peritoneum; and the
lowest third is entirely devoid of peritoneum. The rectum is about
Blood Supply. Five
arteries supply the rectum: the superior hemorrhoidal artery, which is a
continuation of the inferior mesenteric; the 2 middle hemorrhoidals derived
from the internal iliac; and the 2 inferior hemorrhoidals, which are branches
of the internal pudendals. The superior hemorrhoidal {rectal) artery is
a continuation of the inferior mesenteric and begins at the middle of the left
common iliac artery. It enters the root of the medial limb of the pelvic
mesocolon and descends in it to the 3rd sacral vertebra. Here it divides into 2
diverging branches which pass downward, first on the back and then on the sides
of the rectum. These divide into smaller branches which are disposed around the
rectum; they pierce the muscular coat about its middle and descend in the
submucosal to the anal canal. The middle hemorrhoidal {rectal) arteries are
small and inconstant branches of the internal iliac. They pass to the sides of
the rectum and are enclosed within the condensations of the visceral pelvic
fascia which forms the so-called rectal stalks or lateral ligaments of the
rectum. The inferior hemorrhoidal {rectal) artery arises on each side
from the internal pudendal (pudic) artery, which is situated in Alcock's canal.
It supplies the anal canal and the lower part of the rectum, chiefly its
posterior part. The superior hemorrhoidal artery supplies the entire internal
surface and the upper half of the external surface of the rectum, but the
middle and the inferior hemorrhoidal arteries are confined chiefly to the external
surface of the lower half. The middle sacral artery also contributes slightly
to the blood supply of the posterior rectal wall.
ANAL CANAL
The anal canal represents the terminal portion of
the large intestine and is about IV2 inches long. It runs downward and backward
at right angles to the rectum, through the fascia and between the 2 levators
into the perineum, where it opens on the exterior at the anus. Relations. Anteriorly,
in the male, the perineal body (central point of the perineum) separates it
from the transverse perineal muscles, the membranous urethra and the bulb of
the penis; in the female, it is separated from the lower third of the vagina. Posteriorly,
it is related to the anococcygeal body, a collection of dense fibrous
tissue which is situated between the anal canal and the coccyx, and blends
above with the median raphe of the levator ani. On each side the
puborectal (levator ani) muscles separate the anal canal from the ischiorectal fossa.
FIG. The anal canal. The pecten is situated between Hilton's line and
the pectinate line. The 3 parts of the external sphincter ani muscle are
identified.
FIG. The external sphincter muscle and its "three layers."
Landmarks. A
view of the anal canal through the anoscope presents 4 rather definite
landmarks: (1) the anocutaneous line, (2) Hilton's line, (3) the pectinate line
and (4) the anorectal line. The anocutaneous line also has been referred
to as the anal verge. Normally, it is in a state of apposition, the epithelium
surrounding it being thrown into folds by the involuntary action of a muscle
which has been called the "corrugator of the anal skin." Hilton's
(intersphincteric) white line is really more blue in color than white and
is more palpable than visible. It marks the sharp nonmuscular interval which
exists between the internal and the external sphincters and feels like a
depression. It lies halfway between the anal verge and the more superior
pectinate line. Directly above Hilton's line is an area about one eighth to one
third of an inch in width; Stroud has called this "the pecten." It
has been given this name because, arising from its upper edge, there is a
serrated margin that resembles the teeth of a comb. Miles has stressed the
importance of this area because of the heavy deposits of fibrous tissue
underlying it; he believes that it is necessary to cut this stenosing fibrous
ring to cure anal fissures. It is an important anatomic landmark, since it is
the line over which prolapsing masses of mucosa fall through the sphincteric
region. Some authors believe that Hilton's white line is identical with the
pecten. The pectinate line also has been referred to as the dentate
line; it is the upper border of the area just described as the pecten. It has
received its name because of its comblike arrangement brought about by the anal
papillae which are continuous above with the columns of Morgagni. The bases of
the anal papillae are connected by irregular folds which are known as anal
valves. This arrangement forms small pockets between the vertical columns;
these are known as the crypts of Morgagni. The area which has been
described as the pecten, or that area which exists between Hilton's line below
and the pectinate line above, is an important surgical landmark. Pennington has
stated that 85 per cent of all proctologic diseases occur in this area. There
are structural as well as clinical differences which result at this line:
1. Stratified squamous epithelium is found 2. At this
line the external sphincter rebelow this line, and above it is columnar
epithelium. The line itself is said to be covered by transitional epithelium.
3.The sympathetic and the cerebrospinal nerves meet here. The skin distal to the line is supplied by the
inferior hemorrhoidal nerve, which carries pain fibers, but the mucous membrane
proximal to the line is supplied by sympathetic fibers which do not contain
pain fibers. Therefore, any anorectal condition which is associated with pain
must be situated below the pecten. For this reason a carcinoma of the rectum is
"silent," but a fissure-in-ano produces severe pain. 4. Internal
hemorrhoids occur above this line, and external hemorrhoids occur below it. 5.
The line divides the lymphatic drainage. The intestine above the line drains
into the pelvic lymph glands (sacral and hypogastric), but the rectum below it
drains into the superficial inguinal glands by lymphatics which pass around the
inner side of the root of the thigh. This explains the reason that lesions
below the pecten may be associated with inguinal lymphadenopathy, but lesions
above this line do not show such adenopathy. 6. The pecten marks the dividing
line between the superior and the inferior hemorrhoidal vessels. Therefore, the
small veins in the submucosa of the pecten communicate the portal with the
systemic circulation at this point (portacaval communication). 7. Focal
infections take place at this line because this is the location of the crypts
of Morgagni; hence, cryptitis, papillitis and fistulae-in-ano are located here.
8. Developmental defects may be found here. Since the anal canal is formed by a
fusion of an ingrowth of skin from below, known as the proctodeum, and a
downgrowth of hindgut from above, the anal membrane which forms a partition
between these two is located at the pecten. The septum disappears, as a rule,
leaving only the dentate line, but should it remain intact, the membrane then
is visible and separates the hindgut from the proctodeum. The anorectal line
should not be confused with the anocutaneous line. The anorectal line lies
about
VASCULAR SUPPLY OF
FIG. The external sphincter ani muscle: (A) in the male; (B) in the
female.
and the testicular (or ovarian) vessels, which
lie on the psoas fascia. It terminates by dividing into ascending and
descending branches. The descending (ileocecal) branch divides into anterior
and posterior cecal, appendicular and ileal branches. The anterior cecal branch
runs in the superior ileocecal fold of peritoneum in front of the cecum and supplies
this area; the posterior cecal branch supplies the posterior cecal surface. The
ileal branch anastomoses in the mesentery with the end of the superior
mesenteric artery, thus forming a single, or sometimes a double, tier of arches
from which vasa recta pass to the last
FIG. Blood supply
of the large bowel. The branching vessels which pass along the inner margin of
the colon form the so-called marginal "artery" of Drummond.
FIG. Arterial blood supply of the sigmoid and the rectum.
they divide and anastomose with each other. The
lowest sigmoidal branch is connected to the superior hemorrhoidal vessel by a
very small branch. Because of this supposed weak link, there was thought to be
little or no anastomotic connection between the superior hemorrhoidal and the
sigmoidal vessels. This "weak spot" has been called the
"critical point of Sudeck." Formerly, it was believed that ligation
of the superior hemorrhoidal artery below the origin of the lowest sigmoidal
artery would produce a necrosis of the rectosigmoid and the upper part of the
rectum. The "critical point of Sudeck" was discussed in connection
with this. It was thought that the marginal artery, which runs parallel with
the colon, ends abruptly in the region of the lower sigmoid and does not
anastomose with the blood supply from below. Dixon is of the opinion that
although this might appear to be true, it actually is not; hence, he definitely
states that the superior hemorrhoidal artery can be ligated and even some of
the marginal artery resected without damaging the blood supply to the remaining
portion of the descending colon, the rectosigmoid or the rectum. He further
states that all of the colon which lies below the brim of the true pelvis
remains
FIG. Venous drainage of the sigmoid, the rectum and the anus.
viable without the superior hemorrhoidal or
marginal arteries.
Veins. The rectal
veins are arranged in a similar manner to the arteries but differ from those of
the other divisions of the large bowel in that they form a hemorrhoidal
plexus within the thickness of the bowel. This plexus is developed best in
the anal region; it begins inferiorly at the internal margin in a number of
small veins which increase in size and number as they ascend. In the anal canal
the plexus chiefly occupies the columns of Morgagni. In the upper part of the
rectum the venous trunks traverse the muscular layer and end exteriorly where
they unite to form the superior hemorrhoidal vein. This vein drains into
the inferior mesenteric vein and finally into the portal vein; hence, the
greater part of blood from the rectum and the anal canal joins the portal
circulation. The middle hemorrhoidal vein chiefly drains the external
surface of the rectum in its lower half. It accompanies the artery of the same
name and terminates in the internal iliac vein. The inferior hemorrhoidal
vein drains the lower part of the anal canal and joins the internal pudic
(pudendal) vein, which empties into the internal iliac vein. Certain structural
factors are important in the development of varicosities of these veins which
are known as hemorrhoids. They are the absence of valves and the oblique
passage of the veins through the muscular wall; since the greater part of the
venous blood of the rectum returns to the portal circulation, any portal
obstruction alters the return flow. The superior mesenteric vein lies on
the right side of its artery. It begins at the lower end of the root of the
mesentery, passes upward and to the left and receives tributaries which
correspond to the branches of the superior mesenteric artery. The right
gastro-epiploic vein from the greater curvature of the stomach also empties
into it. It leaves the root of the mesentery, crosses in front of the third part
of the duodenum and the uncinate process of the pancreas and terminates behind
the neck of the pancreas by joining the splenic vein to form the portal vein. The
inferior mesenteric vein is a continuation of the superior rectal
(hemorrhoidal); it passes upward on the posterior abdominal wall to the left
side of the inferior mesenteric artery. It receives tributaries which
correspond to the branches of the artery, then curves to the right above the
duodenojejunal flexure, passes behind the body of the pancreas and joins the
splenic vein. The branches of the lower and the upper left colic artery cross
either in front or behind it, but the testicular artery and the genitofemoral
nerve always cross behind it.
RECTAL SURGERY
HEMORRHOIDECTOMY Hemorrhoids or piles are
varicosities of the hemorrhoidal veins. Internal hemorrhoids, or varices of the
superior and the middle hemorrhoidal veins, are covered by mucous membrane and
are above the pectinate line. External hemorrhoids are dilatations of the
inferior hemorrhoidal veins, are covered by skin and appear below the pectinate
(dentate) line. An external pile is usually associated with each of the 3
primary internal hemorrhoids (3, 7 and 11 o'clock). Therefore, in doing a
hemorrhoidectomy a hemostat is placed on the external hemorrhoid; this is
elevated, and an incision is made in the skin. This dissection is carried to
the mucocutaneous junction, and a clamp is placed on the entire internal pile.
A suture is passed beneath the tip of the clamp and tied; this ligates the
nutrient artery. The pile above the clamp is removed, and an over-and-over
suture replaces the hemostat. The suture is made taut, and the 2 ends are tied
together.
ISCHIORECTAL ABSCESS AND FISTULAS Many
authorities are of the opinion that an ischiorectal abscess and a fistula-in-ano
result from an infected crypt of Morgagni. The infection may burrow above,
below or through the sphincter ani muscle. As a result of this burrowing, the
ischiorectal fossa is reached, and here an ischiorectal abscess develops. This
may open spontaneously or is opened surgically, but in either event a
fistula-in-ano with its external opening results. The internal opening
corresponds to the infected crypt. Successful treatment of such fistulas
depends on the eradication of the internal opening as a primary focus of
infection and removal of the fistulous tract. If the tract is subcutaneous, a
fistulectomy can be done. However, if the tract lies deeper and has many
ramifications, a wide excision with healing by secondary intention becomes the
method of choice.
FIG. Internal and external hemorrhoids.
FIG. Types of fistulae-in-ano. The fistula may burrow above, below or
through the sphincter ani muscle. Number 4 represents the horseshoe type of fistula.
FIG. Lymph drainage of the colon. These lymphatics mainly follow the
course of the chief blood vessels. Most of the lymph drainage is to the group
of glands located around the upper part of the superior mesenteric artery; from
here the efferent vessels drain to the main intestinal lymph trunk.
FIG. Extent of resection necessary in malignant lesions involving
portions of the large bowel. (A) Carcinoma of the cecum or the ascending colon
requires removal of the terminal 6 or
FIG. Lymphatic drainage of the rectum. The arrows indicate the 3 zones
of lymphatic spread. Zone 1 travels upward; Zone 2 laterad, between the pelvic
fascia and the levator ani muscle; Zone 3 spreads downward.
FIG. Lymph drainage of the anal canal and the lower rectum. The arrows
indicate the two main courses of lymph flow. Lymph from the lower part of the
anal canal passes across the perineum to the superficial inguinal nodes. Lymph
from the upper part of the anal canal passes upward to the inferior mesenteric
nodes.
SURGICAL CONSIDERATIONS OF THE UTERUS
AND THE ADNEXAE
HYSTERECTOMY Subtotal (Supravaginal)
Hysterectomy. This operation commonly is performed for benign lesions or extensive
inflammatory disease. A low midline incision is made, and the round ligaments
are severed on both sides about 
FIG. Presacral neurectomy. (A) Incision. (B) An incision has been placed
into the posterior parietal peritoneum at the bifurcation of the aorta. The
nerves are severed and dissected downward.
anterior vesical flap. Panhysterectomy. The
steps of this procedure may be similar to those for subtotal hysterectomy until
the uterine vessels are ligated. After this step, the operator examines the
region of the cervix to determine the length of the cervix and the position of
the bladder. The latter is pushed downward, usually by gauze dissection. This
is continued downward and forward until the thumb and the index finger can
compress the vaginal wall below the cervix. The peri
FIG. Subtotal (supravaginal) hysterectomy. (A) The lower midline
incision extends to the left of the umbilicus if necessary. (B) The round
ligaments are severed and tied, and a peritoneal (vesical) flap is formed. (C)
The tubes and the ovarian ligaments are severed and tied. (D) Clamps bite into
and slide off of the cervix; in this way the uterine vessels are secured. (E)
The uterine vessels are severed, and the cervix is coned and cut across. (F) Peritonization.
FIG. Panhysterectomy. (A) A long midline incision extends to the left
and above the umbilicus. (B) The vesico-uterine peritoneum is incised
transversely. The round ligaments may or may not be grasped with the fallopian
tubes and the utero-ovarian ligaments. The finger has perforated an avascular
area in the left broad ligament. (C) The uterine vessels are clamped and cut;
this permits downward displacement of the ureter. (D) The bladder is separated
from the cervix by blunt dissection. (E) The anterior and the posterior
dissections are completed below the cervix. (F) Amputation across the vaginal
vault is done as close to the cervix as possible. (G) Closure of the vaginal
vault with apposition to it of the round and the utero-ovarian ligaments.
toneum on the posterior cervical wall is incised
and dissected downward until the cervix can be palpated through the vaginal
vault. The vagina is entered, and the vaginal vault is divided as close to the
cervix as possible. After freeing the cervix from the vagina, the anterior and
the posterior vaginal walls are approximated. During the closure, the round
ligaments, the tubes and the utero-ovarian ligaments are anchored to the angles
of the vaginal vault. All raw surfaces are carefully peritonized.
SALPINGECTOMY AND SALPINGO-OOPHORECTOMY Removal
of the fallopian tubes and the ovaries usually is done for inflammatory
involvement, cysts, neoplasms, ectopic pregnancies, etc. Salpingectomy. After
exposing the tube, clamps are applied to the outer margin of the mesosalpinx.
It is important that these clamps be placed as close to the tube as possible so
that the vascular supply of the ovary is not interfered with. The mesosalpinx
is cut, and the uterine cornu is excised. The latter is closed, and the
hemostats on the mesosalpinx are ligated. Peritonization is accomplished by
suturing the posterior leaf of the broad ligament to the posterior surface of
the uterus. Salpingo-oophorectomy. When both the tubes and the ovary are
to be removed, the clamps are applied to the infundibulopelvic ligament, which
contains the ovarian vessels. The remainder of the procedure is the same as
that described for salpingectomy.
SURGERY FOR RETRODISPLACEMENT OF THE UTERUS Many
operations have been devised to correct the retrodisplaced uterus. The usual
procedures performed are the Gilliam, the Baldy-Webster, the Olshausen and the
Coffey. Gilliam Operation. After opening the abdomen, a clamp is used to
grasp the round ligaments about
FIG. Salpingectomy.
Olshausen Operation. The
round ligament is picked up by a suture which is carried beneath it about 1
½ inches from the cornua of the uterus; the same is done on the opposite
side. The uterus is brought forward to a point corresponding to its normal
anterior position, and the sutures previously introduced are carried through
the peritoneum, the recti muscles and the aponeurosis about ½ inch to
each side of the median incision. The sutures are tied. This operation also has
a disadvantage in that it leaves 2 apertures between the ligaments and the
anterior abdominal wall; through these openings loops of intestines or omentum
may become strangulated. Coffey Operation.
In this procedure, the folded excess loop of round ligament is sutured to
the anterior surface of the uterus. This suture begins about
FIG. Salpingo-oophorectomy.
FIG. The Baldy-Webster operation for retrodisplaced uterus.
Male perineum
EMBRYOLOGY In the embryo, the endodermal
alimentary tract ends as a blind receptacle called the cloaca; this has an
anterior diverticulum called the allantois (urachus). The mesonephric duct
(adult vas deferens) grows caudally and opens into the anterior part of the
cloaca. The ureter develops as an outpouching of the mesonephric duct, the two
for a period ending in one terminal duct. This common duct subsequently is
absorbed into the wall of the bladder and the prostatic urethra, with the result
that the ureter and the vas deferens eventually have separate openings. A
mesodermal septum (urorectal septum) divides the cloaca into an anterior,
urogenital part and a posterior, intestinal part. The cloaca has a sphincter,
also divided into an anterior portion, which becomes the superficial
transversus perineus, the bulbospongiosus, the ischiocavernosus and the
urogenital diaphragm; the posterior part of the sphincter becomes the external
sphincter ani. One nerve, the pudendal, supplies the cloacal sphincter as well
as the skin of the region around it; its accompanying artery, the pudendal,
nourishes this region. The bladder and the rectum receive their nerve supply
through the pelvic splanchnic nerve and the hypogastric plexus.
The perineum is
a lozenge-shaped space which is bounded by the pubic symphysis, the rami of the
pubes and the ischia, the ischial tuberosities, the great sacrotuberous
ligament, the edges of the great gluteal muscles and the coccyx. If a
transverse line is drawn across the space between the anterior extremities of
the ischial tuberosities, directly in front of the anus, it divides the
perineum into two parts. The anterior part forms a nearly equilateral triangle
which measures approximately 3V4 inches on all sides and is known as the
anterior or the urogenital triangle. The posterior part is also somewhat
triangular; it contains the rectum and the ischiorectal fossae and is called
the anal triangle. The bony framework of the perineum may be felt more or less
distinctly, and in thin subjects the sacrotuberous ligament may even be made
out beneath the
FIG. Embryology of the male urogenital system. (A) An early stage; a
cloaca is present. (B) A later stage; the cloaca has been divided by the
urorectal septum.
FIG. The male perineum.
gluteus maximus muscle. The superficial areas of
the perineum depend on the posture of the body. When the thighs are brought
together, it is very limited and then is represented only by a narrow groove
which contains the anus and the roots of the scrotum and the penis. The region
is wider in the female because of the greater size of the pelvic outlet. In the
midline of the perineum a cutaneous ridge, the median raphe, can be followed
from the front of the anus forward over the scrotum and along the lower surface
of the penis. This raphe marks that line along which the floor of the urethra
was completed and where the two halves of the scrotum fused during their
development.
UROGENITAL TRIANGLE This is the anterior triangle
of the perineum or the genitourinary part. It is bounded in front by the pubic
symphysis, on the sides by the rami of the pubis and the ischium, and
posteriorly by a line drawn between the anterior parts of the ischial
tuberosities. The superficial fascia consists of 2 layers: an outer
fatty layer and an inner membranous layer. The superficial fatty layer of
the superficial fascia is continuous with the superficial fat of the rest of
the body and contains small cutaneous vessels and nerves. The farther downward
this layer is traced the scarcer becomes the fat, so that over the scrotum the
fat entirely
FIG. Colles' fascia. This fascia is the deep layer of superficial
fascia; on the anterior abdominal wall it is called Scarpa's fascia. This
fascia determines the direction of spread of extravasated urine
disappears and gives place to a thin layer of
involuntary muscle fibers. These constitute the dartos muscle and are
responsible for the rugosity of the scrotal skin which is caused by their
contraction. The deep layer of superficial fascia is not fatty but
membranous and is continuous with a similar lyer of fascia in the lower part of
the anterior abdominal wall. In the anterior abdominal wall it is called
Scarpa's fascia but changes its name in the perineum to the fascia of Colles;
it is found only over the urogenital triangle. Its attachments are to the
fascia lata, the pubic arch and the base of the perineal membrane. It is
prolonged over the penis and the scrotum and so forms a covering for the testis
and the spermatic cord. The arrangements and the attachments of this fascia are
important because they determine the direction in which extravasated urine will
spread after rupture of the cavernous portion of the urethra. The fascia has a
median septum which attaches to the perineal muscles, but this septum is not
complete, and fluid may pass through it from side to side. Urine under Colles'
fascia following rupture of the urethra may extend downward as far as the lower
border of the urogenital diaphragm because at this point it fuses with the base
of the diaphragm. Laterally, it may extend through the median septum as far as
the attachment of the fascia to the conjoined ischiopubic rami; upward, it may
extend over the scrotum and the penis and onto the anterior abdominal wall.
Once the fluid has reached the anterior abdominal wall it can extend downward
and over the inguinal ligament until it is held up by the attachment of
Scarpa's fascia to the fascia lata approximately
THE SUPERFICIAL PERINEAL POUCH The superficial
perineal pouch is a compartment in the urogenital part of the perineum which is
bounded inferiorly (a floor) by Colles' fascia and superiorly (a roof) by the
urogenital diaphragm (perineal membrane). The pouch is closed behind by the
fusion of its roof and floor, and on each side by the attachments of the walls
to the margins of the pubic arch. Above, however, it remains open and
communicates with the cellular interval which is situated between Scarpa's
fascia and the anterior rectus sheath. Should the urethra rupture into this
space, it would fill the posterior part of the pouch and then spread into the
scrotum and the penis and, if allowed to continue, would ascend in front of the
symphysis pubis and so reach the anterior abdominal wall. The contents of the
superficial perineal compartment consist of the roots or fixed portions of the
corpora cavernosa of the penis and the urethra, their overlying
ischiocavernosus and bulbocavernosus muscles, the superficial transverse perineal
muscles and those branches of the internal pudendal vessels and nerves which
pierce the inferior fascia of the urogenital diaphragm to reach this space. The
2 roots of the corpora cavernosa of the penis arise from the midportion of the
ischiopubic rami, run obliquely upward and forward and adhere to the periosteum
of the descending rami of the pubes and to the inferior surface of the
urogenital diaphragm. Each cavernous body is covered by the ischiocavernosus
muscle. Superficial Perineal Muscles. On each side, the following 3
superficial perineal muscles lie in the superficial perineal pouch. 1. The
superficial transverse perineal muscle lies at the base of the pouch and
extends from the ischial tuberosity to the central point of the perineum. The 2
transverse muscles act together to steady the perineal body during defecation
and to fix it during contractions of the external sphincter and the
bulbospongiosus. 2. The ischiocavernosus muscle is applied to the cms
and arises close to the superficial transverse perineal muscle; it covers the
free surface of the crus into which it is inserted anteriorly. The 2
ischiocavernosus muscles compress the crura against the pubic arch and so
obstruct the venous return of the corpora cavernosa. 3. The bulbocavernosus
{bulbospongiosus) muscle arises from the perineal body and from a median
raphe which separates the 2 halves of the muscles on the inferior surface of
the bulb. Therefore, it is a bilateral structure. The most posterior fibers of
this muscle pass to the perineal membrane, the intermediate fibers of the 2
sides meet on the dorsum of the corpus spongiosum, and the most anterior fibers
meet on the dorsum of the penis where they blend with the fascia of the penis.
This muscle acts as a sphincter which empties the bulb and part of the spongy
urethra and also compresses the bulb
FIG. The superficial and the deep perineal pouches.
FIG. The superficial perineal pouch and its contents. Colles' fascia has
been incised and reflected to reveal the contents of this pouch.
against the perineal membrane, thereby
constricting the corpus spongiosum. All the superficial perineal muscles are
supplied by the perineal branch of the pudendal nerve. The perineum on each
side of the corpus cavernosum urethra is traversed by nerves and vessels which
are small branches of the pudendal trunks. They supply the surrounding
structures in the superficial perineal compartment.
DEEP PERINEAL POUCH (UROGENITAL DIAPHRAGM) The
urogenital diaphragm is a musculomembranous diaphragm which is stretched
tightly across the pubic arch and is attached.
FIG. The bulbo-urethral gland (Cowper). The gland is situated between
the layers of the urogenital diaphragm. If the gland suppurates, it may
evacuate into the urethra, the perineum or the rectum.
FIG. The internal pudendal artery. This artery gives rise to the dorsal
artery of the penis, the deep artery of the penis and the artery to the bulb.
The dorsal nerve of the penis accompanies the internal pudendal artery.
to the ischiopubic rami. It separates the
perineum from the pelvis and consists of 2 layers of fascia with 2 muscles
between them. The 2 fascial layers are the superior (upper) and the inferior
(lower) layers; the 2 muscles are the sphincter urethrae membranaceae and the
deep transverse perineal. The space which is created by these 2 layers of
fascia and is filled by the 2 muscles is known as the deep perineal pouch or
compartment. The inferior fascial layer of the urogenital diaphragm also
has been referred to as the superficial layer of the triangular ligament and
the perineal membrane. It covers the lower surface of the sphincter urethrae
and the deep transverse perineal muscle. Its lower surface is largely covered
by the root of the penis, and each side is attached to the side of the pubic
arch. Its posterior border is fused with the posterior border of the superior
fascia of the urogenital diaphragm and the membranous layer of superficial
fascia. In the midline, the fused borders are continuous with a fatty
fibromuscular nodule called the perineal body. Anteriorly, this fascia
presents a thickened free margin known as the transverse perineal ligament;
between this ligament and the inferior ligament of the
pubis there is an oval interval through which the
deep dorsal vein of the penis passes into the pelvis to enter the venous
network around the prostate. The membrane is pierced by several structures
which enter the superficial perineal pouch: (1) the urethra pierces it in the midline
about
External Genitalia
PENIS The penis has a posterior fixed part or
root and an anterior mobile portion called the body. It is composed of 3
fibroelastic cylinders which are filled with spongy or erectile tissue. These
cylinderlike masses are the right and the left corpora cavernosa and the corpus
spongiosum (urethrae). Corpora Cavernosa. The 2 roots of the corpora
cavernosa of the penis arise from the midportion of the ischiopubic rami, pass
obliquely upward and forward, hugging the periosteum of the descending rami of
the pubes and the inferior surface of the urogenital diaphragm. Each is covered
by the ischiocavernosus muscle. The corpora are united, side by side, in the
body of the penis, but at its root they are separate and assume the name of
crura, each of which tapers to a point posteriorly. The corpus spongiosum, which
is much more slender, lies along the lower surface of the united corpora cavernosa
and is traversed lengthwise by the longest of the 3 divisions of the urethra.
Anteriorly, at the end of the penis, it enlarges to form the glans of
the penis, in which the anterior ends of the corpora cavernosa are embedded. Body.
The body of the penis is formed by the union of all the cavernous masses;
it begins at the apex of the urogenital diaphragm and is attached to it by
connective tissue bands. The corpora cavernosa lie side by side on the dorsum,
and the corpus spongiosum lies ventrally. The corpus spongiosum terminates
posteriorly in a large, free bulbous sac known as the bulb of the urethra.
This latter structure overlaps the junction of the membranous and the cavernous
divisions of the urethra posteriorly.
SUPERFICIAL STRUCTURES Prepuce. The skin
of the penis is continued forward as the prepuce (foreskin). The skin is devoid
of hair, and the fascia is devoid of fat. The prepuce is a fairly dense portion
of skin which forms a cuff or
FIG. The superficial structures of the penis. The penis has 3
superficial encircling coats: the skin, the loose areolar subcutaneous tissue
and the fascia of the penis (Buck's). These have been reflected in the drawing.
hood covering the glans. Within the cavity of the
prepuce the modified skin contains sebaceous glands which secrete smegma. Frenulum.
On the under aspect of the glans a well-defined fold of skin called the
frenulum passes forward and is attached to the prepuce. The subcutaneous tissue
of the penis, a continuation of Colles' fascia, is very loose in texture and is
traversed by the superficial dorsal vein. The looseness of these tissues gives
mobility to the penis and explains the ease with which blood or urine may
extravasate, producing tremendous swellings of the organ. The superficial
lymphatics accompany the superficial dorsal vein and enter the subinguinal
lymph nodes. These become involved in infections about the prepuce and the
glans. Buck's Fascia. Beneath the subcutaneous layer, the penis is
invested by a thin fibrous membrane known as the fascia of the penis (Buck's
fascia). This fascia envelops the body of the penis and the corona of the glans
to the root of the penis. It is adherent on each side in the groove between the
corpora cavernosa and the corpus spongiosum. The suspensory ligament of the
penis is a thickened, triangular, fibroelastic band. It is fixed above to
the lower part of the linea alba and the upper part of the symphysis pubis;
below, it splits to form a sling for the penis at the junction of its fixed and
mobile parts where it blends with the fascia of the penis. The deep dorsal
nerve, arteries, veins and lymph vessels run beneath Buck's fascia and
along the dorsum of the penis. Encircling branches of the veins drain the
corpora cavernosa and the corpus spongiosum, and encircling arteries send twigs
to the same structures. The deep dorsal vein passes between the
intrapubic ligament and the urogenital diaphragm to the prostatic venous
plexus. On the dorsum of the penis a pair of dorsal nerves pass lengthwise
beneath the deep fascia; between these there is a pair of dorsal arteries, and
between these the deep dorsal vein lies in the median plane. The superficial
dorsal vein, also median, lies in the superficial fascia and is the one
which is seen through the skin. It should be noted that the veins are not left
and right, as are the arteries and the nerves, but are median, either
superficial or deep. The superficial dorsal vein receives tributaries from the
skin and the prepuce and terminates posteriorly by dividing into right and left
branches which drain into the external pudendal veins in the thigh. The deep
dorsal vein begins by the union of several twigs from the glans and the
prepuce. It runs backward in the median line, passes between the 2 layers of
the suspensory ligament and enters the pelvis after passing below the inferior
pubic ligament. It ends by joining the venous plexus which surrounds the
prostate. The dorsal arteries of the penis are the terminal branches of
the internal pudendal. They pass forward in the interval between the corpora
cavernosa and reach the dorsum of the penis. Here the 2 arteries lie one on
each side of the deep dorsal vein. The dorsal nerve lies lateral to the artery;
both vessels and nerves are enclosed between the 2 layers of the suspensory ligament
of the penis. These vessels supply the body of the
FIG. The venous drainage of the penis. (A) Lateral view of the relations
between the superficial and the deep dorsal veins. (B) Cross section showing
relations of vessels to the fasciae.
FIG. The tunica albuginea and Buck's fascia: (A) cross section, (B)
relations to the urogenital diaphragm, (C) sagittal view.
FIG. The male
urethra. The urethra is divided into prostatic, membranous and penile parts.
The relations of each part are shown in sagittal section.
penis and terminate in the glans. The deep artery
of the penis pierces the medial aspect of the anterior part of the eras and
runs forward in the corpus cavernosum penis. Each dorsal nerve of the
penis is a terminal branch of the pudendal nerve. It supplies branches to the
corpus cavernosum, the glans and the skin of the penis. Tunica Albuginea. Each
erectile body is surrounded by a distensible elastic fibrous tissue called the
tunica albuginea, the trabeculae of which surround blood spaces. Where the
corpora are applied against each other, the albuginea forms a median partition
called the septum of the penis. It is difficult at times to differentiate or
separate Buck's fascia from the tunica albuginea.
URETHRA The urethra is a fibro-elastic structure
which measures about
FIG. The penile portion of the urethra after it pierces the urogenital
diaphragm.
bulb about
FIG. The posterior wall of the male urethra.
FIG. The scrotum and its 6 associated layers: (A) side view; (B)
schematic cross section.
in pathologic conditions which involve either the
urethra or the prostate gland.
SCROTUM The scrotum is a pendulous purselike bag
of skin and fascia in which the testes are found. It has a bilateral origin,
being derived from right and left labioscrotal folds. In the female, these
folds remain separated as the labia majora, but in the male they fuse behind
the penis to form the scrotum. A vestige of the fusion of the 2 sides of the
scrotum remains as the median raphe, which is continued into the perineal skin
behind the scrotum and along the lower aspect of the penis anteriorly. The
skin of the scrotum forms a single pouch. It is delicate in texture, darker
in color than the surrounding region and quite distensible. Its rugosity, which
varies with temperature, is produced by the dartos muscle, which lies
immediately subjacent. Fascia. The superficial fascia in the
scrotum is entirely devoid of fat and is largely replaced by the thin sheet of
muscle just mentioned, the dartos. This muscle sends a median partition across
the scrotum which separates the testes from each other; however, the septum is
incomplete superiorly. It is a laminated thin sheet of involuntary muscle which
is platysmalike, since it is intimately adherent to the skin, causing it to
wrinkle. It contracts with cold and relaxes with heat, its tonicity decreasing
with age. Sympathetic nerve fibers supply it. In the wall of each scrotal
chamber there are, besides skin and dartos, 3 complete layers which are derived
from the anterior abdominal wall. They are, named from without inward: the
external spermatic fascia, the cremaster muscle and the internal spermatic
fascia. These provide additional coverings or coats for each testis. The
external spermatic fascia, which is derived from the external oblique
aponeurosis, appears as a small layer of areolar tissue situated directly under
the dartos. Though the skin and the superficial fascia are common to both
halves of the scrotum, the 3 additional layers are confined to each
corresponding side because of the septum produced by the dartos muscle. The
cremaster muscle is derived from the internal oblique. Its muscle loops reach
the testicle as thin strands. By their contraction the testis is drawn toward
the subcutaneous
FIG. The testis. (A) A section of the gland has been removed to show its
relations to the epididymis and the tunica albuginea. (B) and (C) Coverings of the
spermatic cord and the testis.
inguinal ring and produces the cremasteric
reflex. The internal spermatic fascia is derived from the transversalis
fascia. It is composed of loose connective tissue and closely invests the
elements of the cord and the testicle. The tunica vaginalis testis is
developmentally a portion of the peritoneum. It is a serous membrane and, like
all other serous membranes, has parietal and visceral layers; these are
separated by a capillary interval which contains a film of fluid which keeps
the surfaces moist. The parietal layer lines the wall of the scrotum and is
closely adherent to the internal spermatic fascia. At the back of the scrotum
it is reflected forward and becomes continuous with the visceral layer.
The latter covers the epididymis and then the testis itself. In inguinal
herniae of long standing, the coats of the testis and the spermatic cord become
thickened and may be separated and displayed, but in normal individuals,
although the dartos and the tunica vaginalis are identified easily, the
external spermatic fascia, the cremaster and the internal spermatic fascia have
a tendency to become fused and are defined less easily.
TESTIS This gland appears as an oval body with
flattened sides; it lies in the scrotum with its long axis oblique, its upper
pole tilted forward. It varies in size, but its average dimensions are 1
½ inches in length,
FIG. The internal structure of the testis. (A) Transverse section of the
right testis. (B) Teased sagittal section.
mediastinum, incomplete fibrous septa pass inward
to subdivide the gland into lobes. Convoluted seminiferous tubules lie in the
lobes and pass backward into the mediastinum testis, where they unite and form
a network called the rete testis. From this network about 20 efferent
ductules (vasa efferentia) arise; they emerge from the upper pole of the testis
and enter the head of the epididymis. The epididymis is applied to the
upper pole and the posterior border of the testis. It tapers from above
downward and is subdivided into a head, a body and a tail. The head of the
epididymis is enlarged and fits like a cap on the upper pole of the testis, to
which it is attached by the efferent ductules. The body is separated from the
testis by the sinus of the epididymis, and the tail or lower end is attached
only by areolar tissue near its lower end. Within the head, the efferent
ductules unite to form the canal of the epididymis, which is coiled up within
the body and the tail. When unraveled, it measures almost
SPERMATIC CORD This appears as a long, rounded
bundle which extends from the deep inguinal ring to the posterosuperior border
of the testicle. Within the abdomen its constitutent parts are widely
separated, but from the deep inguinal ring
FIG. The blood supply of the testis and the constituents of the
spermatic cord.
to the testis they are wrapped together by the
coverings of the cord. It is encased in 3 fibrous coats derived from the
abdominal wall during the descent of the testis, namely, a continuation of the
external abdominal oblique (the external spermatic fascia), a continuation of
the internal abdominal oblique (the cremaster muscle), and a continuation of
the transversalis fascia (the internal spermatic fascia). Plus this, the 2
inner layers of the abdominal wall, namely peritoneum and preperitoneal fat,
are also present. In the fatty layer run the duct, the vessels and the nerves
of the testis, and the vessels and the nerves of the epididymis. These
constituents of the cord assemble at the internal inguinal ring lateral to the
inferior epigastric artery, pass through the inguinal canal and descend in the
scrotum to the testis. The cord lies behind the internal oblique laterally and
in front of it medially. As it emerges from the superficial inguinal ring it
passes over the pubic tubercle and covers it; hence, when one attempts to feel
the tubercle, it is first necessary to displace the cord. The constituents of
the spermatic cord are: 1. Continuations of the 2 inner layers of the abdominal
wall (processus vaginalis peritonei and the preperitoneal fatty areolar
tissue). 2. Structures associated with the testicle (vas deferens and artery,
veins, lymphatics and nerves). 3. Vessels and nerves associated with the vas
deferens and the epididymis. The processus vaginalis peritonei (funicular
process of peritoneum, tunica vaginalis testis) is a tubelike process of
peritoneum, the upper part of which lies in front of the vas; it is obliterated
before birth or within a month thereafter to become a fibrouslike thread. Its
lower part remains patent and is invaginated from behind by the testis,
changing its name to the tunica vaginalis testis. The preperitoneal fatty
areolar tissue is an extension of the extraperitoneal abdominal fat which
surrounds the processus vaginalis and forms a covering for the structures which
pass to and from the testis. This layer is the surgeon's landmark to the
underlying "sac" in inguinal hernia operations. The adipose tissue in
this layer diminishes as one proceeds down the cord; thus, no fat is found in
the scrotum. The vas deferens (ductus deferens) is the structure which
conveys spermatozoa from the testis to the urethra; it is as long as an adult
femur. It starts in the tail of the epididymis, of which it is the
prolongation; the pathologic changes of one affects the other. It is the only
hard structure in the spermatic cord; hence, it can be identified easily; the
firmness is due to a thick muscular coat. It has a tiny lumen and is dilated at
its two extremities, which are the only thin-walled portions of the vas. It
first ascends behind the testis along the medial border of the epididymis,
continues through the scrotum and the inguinal canal as the posterior
constituent of the spermatic cord, then winds around the lateral side of the
inferior epigastric artery and descends to the posterolateral angle of the
bladder, and thence to the urethra. The vas is subperitoneal throughout its
entire course. Normally, it is bluish white in color, resembling cartilage.
Because of its posterior relationship, the sac of an indirect inguinal hernia
usually lies anterior to it. ARTERIES There are two arteries in the
spermatic cord, namely, the testicular and the deferential arteries. The
testicular (internal spermatic) artery is the larger and supplies the testis.
It arises from the abdominal aorta in the lumbo-iliac region and joins the cord
at the abdominal inguinal ring. In the cord it is surrounded and hidden by the
spermatic group of veins. It lies in front of the vas. The artery of the vas
deferens is a slender branch of the inferior vesical artery which passes along
the vas to supply it and the epididymis. VEINS The pampiniform plexus
represents the veins of the testis and the epididymis; they number about a
dozen. This anastomosing plexus receives its name from its resemblance to a
vine. The veins ascend in 3 longitudinal groups. The anterior group surrounds
the testicular artery, and the middle surrounds the vas; the posterior group
runs alone. As the veins ascend they decrease in number but increase in size
and finally end at or near the deep inguinal ring as the testicular vein, which
continues upward over the posterior wall of the abdomen. The right vein ends in
the inferior vena cava, the left joins the left renal vein. In the lower part
of the abdomen they are frequently double. On the right, the vein empties into
the inferior vena cava near the renal pedicle; on the left, it enters the renal
vein almost at a right angle. This fact explains the increased incidence of
varicoceles on the left side as compared with the right. LYMPHATICS The
lymphatics of the cord and the testicle follow the spermatic vessels throughout
their course and end in the external iliac glands or the lumbar nodes about the
aorta and the inferior vena cava. In addition to the structures just discussed,
a cremasteric artery exists; it arises from the inferior epigastric
artery close to the deep inguinal ring and supplies the coverings of the cord.
NERVES The genital branch of the genitofemoral nerve (L 1 and 2)
supplies the cremaster muscle and a sensory branch to the tunica vaginalis. Sympathetic
fibers from the renal and the aortic plexuses carried by the testicular
artery, and from the pelvic plexus carried by the artery to the vas, supply
branches to the testis (T 10) and to the epididymis (T 11, 12 andL 1).
SURGICAL CONSIDERATIONS
VARICOCELECTOMY A varicocele is a dilatation and
varicose condition of the spermatic veins (pampiniform plexus). It is more
common on the left than on the right side. The veins usually involved are the
anterior group which surround the testicular artery. To perform
FIG. Varicocelectomy.
FIG. Hydrocelectomy.
the operation an incision is made low in the
inguinal region. The spermatic cord is located at the external inguinal ring
and drawn into the wound. The coverings of the cord are incised, and the veins
are exposed; two thirds of the veins involved are doubly ligated, and the
intervening segment is removed. The ends of the severed veins are brought
together, thus supporting the testicle. It is important to make certain that at
least one large vein or group of veins remains so that some return venous flow
is preserved.
HYDROCELECTOMY This operation is done for a
collection of fluid which is found between the layers of the tunica vaginalis
(vaginal hydrocele). Other types of hydrocele have been described. The usual
operation performed is the so-called "bottle" operation. The incision
is made through the skin, the dartos and the superficial fascia; it is placed
directly in the scrotum and over the hydrocele. The testicle with its tunica
vaginalis is exposed, the fluid is aspirated, and the tunica is opened. The
parietal layer of the tunica vaginalis is excised partially, but enough is
permitted to remain so that it may be everted and sutured behind the testicle
and the spermatic cord. In this way, the secreting surface faces outward.
CIRCUMCISION Before the operation is attempted,
the prepuce should be freed from the glans, since adhesions might be present
and result in an unsatisfactory operation or injury to the glans. The redundant
prepuce is placed on tension and amputated parallel with the corona. The
redundant inner layer is mucous membrane and should be excised. The remaining
tissue is folded back and sutured to the skin of the shaft of the penis. An
alternate method of dorsal slit may be utilized
FIG. Circumcision.
Female Perineum
The perineum is a region at the inferior end of
the trunk which is situated between the thighs and the lower part of the
buttocks. It is a diamond-shaped space at the angles of which are found the
inferior pubic (arcuate) ligament above, the tip of the coccyx below, and the
ischial tuberosities at each side. The pubic arch and the sacrotuberous
ligaments form its sides, but the latter are hidden by the gluteus maximus
muscles. If a line is drawn from the anterior part of one ischial tuberosity in
front of the anus to the anterior part of the other tuberosity, this
diamond-shaped area becomes conveniently divided into an anterior urogenital
triangle and a posterior anal triangle. The anal triangles are about the same
in both sexes, but the urogenital triangles differ. On the surface the
urogenital triangle is bounded by the mons veneris in front, by the gluteal
region (buttocks) behind and by the femoral region (thigh) at each side.
THE UROGENITAL REGION
EXTERNAL GENITALIA The mons veneris is a
cushionlike eminence on the front of the pubes; it is produced by a collection
of fatty tissue under the skin. It is covered with hair which ceases abruptly
as the mons merges with the anterior abdominal wall. Pudendum (Vulva). This
collective term includes the labia majora, the labia minora, the body and the
glans of the clitoris and the vaginal orifice. It extends from the pubes above
to a point in front of the anus below. The labia majora are homologous
to the halves of the scrotum in the male; the line of the intervening
vestibular or pudendal cleft between the 2 labia corresponds to the scrotal
raphe. In mulliparae these labia are in contact with each other, and are
therefore the only visible part of the external genitalia. Each labium is a
broad rounded cutaneous
FIG. The female perineum.
fold which lies lateral to the labium minus and
covers a long fingerlike process of fat. The two large labia are united below
the mons veneris (mons pubis) and form the anterior commissure; they are
connected posteriorly and form a narrower and less distinct posterior
commissure. The outer convex surface is covered by ordinary skin and hair
and is provided with numerous sebaceous glands, but the inner surface, which lies
against the opposite labium, possesses a more delicate skin with large
sebaceous follicles. The elevation of the labium is produced by the presence of
a diverticulum of fat which is a continuation of the superficial fat of the
inguinal region. This fatty fingershaped process is demarcated from the
surrounding fat in which it is embedded; it rests against the deep layer of
superficial fascia. The labia minor a {nymphae) are cutaneous folds
which lie medial to the labia majora. The minor lips enclose the vestibule, and
in the young they are commonly concealed by the approximated majora. In older
women and multiparae they are not infrequently pendulous and externally
visible; they are shorter and thinner than the labia majora and become highest
near their anterior end. The anterior extremities each split into two layers,
the upper of which meet above the clitoris to form the prepuce; the
lower layers become attached to the inferior aspect of the glans of the
clitoris and form its jrenulum. The labia minora diminish in size as
they pass posteriorly and blend with the labia majora. In front of the
posterior commissure they are connected by a transverse fold of skin, the
frenulum of the labia (fourchet). Immediately anterior to and above this fold,
between it and the posterior limit of the vaginal orifice, a shallow depression
is formed which is known as the fossa navicularis. These labia are
hair-free and resemble mucous membrane. The clitoris is the female penis
and lies at the apex of the vestibule. Only a small part of the body and the
glans are visible when the labia minora are retracted, since the labia and the
mons hide the greater part of this structure. The vestibule of the
vagina is the cleft which exists between the labia minora. It is a fissure
which is placed anteroposteriorly and into which the urethral orifice opens
above and the vaginal orifice below. On each side, the entrance of the two
minute ducts of the corresponding Bartholin glands are found. The urethral
orifice also has been referred to as the external urinary meatus; it
appears as a vertical slitlike or ovoid opening about 4 or
FIG. The female external genitalia.
It is about
FIG. The superficial anatomy of the urogenital region. On the right side
(reader's left) the superficial layer of superficial fascia has been incised
longitudinally to expose the continuation of the superficial inguinal fascia
which appears as a fatty diverticular process; this process accounts for the
labial elevation. On the left side (reader's right) the 2 layers of superficial
fascia and the superficial musculature are demonstrated.
by becoming firmly attached to the ischiopubic rami
and the ischial tuberosities. On the same plane, but laterally placed, is the
fascia lata of the thigh; the deep layer of superficial fascia joins the fascia
of the urogenital diaphragm behind. The superficial perineal pouch is a
space or compartment which exists between the perineal membrane and the deep
layer of the superficial perineal fascia. This space is bounded interiorly by
the membranous layer of fascia which forms its floor; it is bounded superiorly
by the perineal membrane which forms its roof, and laterally by the side of the
pubic arch between the attachments of these 2 membranes. It is closed
posteriorly by their fusion. Anteriorly, however, the pouch remains open and is
continuous with that interval which exists between the superficial fascia of
the anterior abdominal wall and the aponeurosis of the external oblique muscle,
the interval being filled with areolar tissue. Each half of the pouch contains
a crus of the clitoris, the bulb of the vestibule, the greater vestibular gland
and the superficial perineal muscles, nerves and vessels. Through the
compartment and in vertical directions, in the median plane, pass the terminal
portions of the urinary and the genital tracts. The only portion of the
clitoris which is visible when the labia are retracted is the small end known
as the glans and a small part of its body. The other constituents of this
erectile tissue, with the investing musculature, are in the superficial
perineal compartment and are brought into view only when the deep layer of the
superficial perineal fascia and the inferior perineal fascia are incised. The
crus of the clitoris corresponds to the crus penis, although much diminished in
size. Like the male structure, it is covered by the ischiocavernosus muscle.
The crura are continuous with the corpora cavernosa at the lower part of the
pubic symphysis; the crura are large in comparison with the corpora. On the
symphysis each crus passes backward and laterally to taper at a point near the
lower end of the ischium. It lies on the lower surface of the perineal membrane
along the side of the pubic arch whose perineal surface is grooved to
accommodate it. It is adherent to both the bone and the membrane and is hidden
by the overlying ischiocavernosus muscle. The laterally placed corpora
cavernosa fuse anteriorly to form the small unpaired body of the clitoris. This
is bent upon itself and tapers distally where it is covered by the glans. The
clitoris is supplied with a suspensory ligament which passes upward to the
symphysis and onto the anterior abdominal wall. The glans, like
FIG. Deeper dissection of the urogenital region. The contents of the
superficial perineal pouch are shown. On the reader's right the inferior fascia
of the urogenital diaphragm has been incised to show the relation of the deep
transverse perineus muscle.
FIG. The 3 layers of the perineal musculature. (A) The first layer with
its 3 superficial muscles. (B) The urogenital diaphragm. This diaphragm
consists of an inferior layer of fascia, a deep transverse perineus muscle and
a superior layer of fascia. The inferior fascial layer has been incised to show
the relations. The deep transverse perineus muscle continues upward as the
sphincter urethrae muscle. (C) The third layer consists of the puborectal
portion of the levator ani muscle; it is necessary to cut through the
urogenital diaphragm to visualize this structure.
the homologous male organ, has a frenum and a
prepuce. The bulb of the vestibule corresponds to the bulb of the penis,
but because of the presence of the vagina, it has become a bilateral structure.
These appear as 2 oblong masses of erectile tissue which lie on the inferior
aspect of the perineal membrane and in contact with the lateral walls of the
vagina. They are covered by the bulbocavernosus muscles, and where they are in
close contact with the Bartholin glands they are rounded. In front where they
pass to the sides of the urethra and unite near the body of the clitoris they
are pointed. The 2 halves are united in front of the urethra by a venous plexus
called the pars intermedia. The muscles which cover the bulb are the
superficial and deep transverse perineal muscles plus the external sphincter of
the anus converge to a central point. This is a musculotendinous point which is
located in the midline of the perineum, anterior to the anus at the posterior
limit of the superficial perineal compartment. The fibers of this
musculotendinous portion, plus the tissue between the anal and the vaginal
canals, constitute the perineal body. The greater vestibular glands
(Bartholin) correspond to the bulbo-urethral (Cowper's) glands of the male
but differ in position and in the termination of their ducts. They are about
MUSCULATURE OF THE PERINEUM AND THE PELVIS It is
helpful to consider the perineal muscles as being arranged in 3 separate strata
or layers. There is a superficial layer which consists of 3 muscles: the
superficial transverse perineal, the bulbocaveinosus and the ischiocavernosus.
The middle layer (urogenital diaphragm) consists of the sphincter of the
urethra and the deep transverse perineal plus its fascia; the deep layer is the
levator ani and the coccygeus, which have been discussed elsewhere. The
superficial transverse perineal muscle lies along the base of the
urogenital diaphragm, is at times difficult to define and even may be absent.
It is a slender fasciculus which originates from the ramus of the ischium close
to the tuberosity, passes medially and inserts into the perineal body, at which
point it fuses with its fellow of the opposite. Posteriorly, it lies against
the external sphincter of the anus; anteriorly, it almost reaches the posterior
wall of the vagina. If visible, it is a good surgical landmark, since the
pudendal nerve and artery wind around its posterior border to turn upward and
reach the urogenital region. At this point the nerve may be blocked for
surgical and obstetric procedures, as well as for the relief of pruritus
vulvae. The ischiocavernosus muscle arises from the medial aspect of the
ischium close to its tuberosity, extends forward over the crus and becomes
aponeurotic. As these fibers pass upward they ensheath and insert into the
medial and the inferior surfaces of the crus and extend as far forward as the
body of the clitoris. These 2 muscles compress the crura, thereby retarding the
outflow of blood and assisting in the production of an erection of the
clitoris. They are smaller than the corresponding muscles of the male. The
bulbocavernosus muscle has also been referred to as the bulbospongiosus and
the sphincter vaginae. In the male, the bulbocavernosus is a single structure,
but in the female it is halved symmetrically by the vestibule, and each side
becomes closely related to the lateral surface of the vestibular bulbs. The
fibers originate from the central tendinous point, separate, pass forward on
the walls of the vestibule and converge toward the midline in front, where they
are attached to the body of the clitoris; they cover the bulbs of the vestibule
and act as constrictor muscles of the erectile tissue, as does the
ischiocavernosus. The 3 superficial perineal muscles are supplied by the
perineal branch of the pudendal nerve.
FIG. The internal pudendal artery and its branches.
UROGENITAL DIAPHRAGM The urogenital diaphragm
(triangular ligament) consists of 2 layers of fascia with 2 intervening
muscles. The lower layer of fascia is the inferior layer, and the upper layer
constitutes the superior fascia. The interposed muscles are the deep transverse
perineal and the sphincter urethrae membranaceae. The space between the 2
layers of fascia not only contains the deep transverse perineal muscles but
also encloses the space which is called the second or the deep compartment of
the perineum. The inferior layer (perineal membrane) of the urogenital
diaphragm is the more superficial of the 2 fascial layers and forms the roof of
the superficial and the floor of the deep perineal compartments; laterally, it
attaches to the ischiopubic rami. Medially, it is attached to the sides of the
vagina; posteriorly, the 2 halves of the membrane join behind the vagina; their
posterior borders fuse with the posterior borders of the fascia above the deep
transversus and the membranous layer of the superficial fascia. This fusion
closes the deep perineal pouch posteriorly. Anteriorly, the halves meet in
front of the vagina and the urethra, and their borders fuse with the anterior
borders of the fascia above the sphincter urethrae. The fused anterior borders
are thickened to form a band called the transverse ligament of the perineum;
this is separated from the inferior ligament of the pubis by an oval interval
which transmits the dorsal vein of the clitoris. The inferior layer of fascia
is pierced in the midline by the urethra, the vagina, to either
FIG. The pudendal nerve and its branches.
side by the internal pudendal vessels and the
pudendal nerves, and by branches of these to the erectile tissue of the bulb,
the crus and the glans. The superior layer of the urogenital diaphragm
(upper lamina) also has been referred to as the deep layer of the triangular
ligament. It forms the roof of the deep perineal compartment and the floor of
the anterior extension of the ischiorectal on either side of the midline. It is
derived from the parietal layer of the pelvic fascia. Anteriorly conjoined with
the inferior layer, it forms the transverse ligament of the pelvis; behind, it
again becomes continuous with the inferior layer around the deep transverse
perineal muscles and by means of this fusion attaches to the deep layer
(Colles') of superficial fascia. At the sides it meets the obturator fascia.
Medially and above, it joins the fascial coverings on the under surface of the
levator ani muscle. The deep perineal compartment is the pouch which
exists between the 2 layers of deep fascia of the urogenital diaphragm of the
perineum. Tt contains the deep transverse perineal muscle, the sphincter muscle
surrounding the membranous portion of the urethra, and the pudendal vessels and
nerves. The sphincter muscle of the membranous urethra (sphincter urethrae
membranaceae) is not named entirely correctly, since it would indicate that
it is related only to the urethra, but in reality it sends fibers to the
vaginal and the anal canals as well. The muscles arise on each side from the
ischiopubic rami, and as they approach the midline, an anterior group passes to
the urethra, almost reaching the inferior margin of the symphysis pubis. More
posteriorly, a group becomes implanted into the urethra; similarly, a group of
fibers is related to the vagina; the postvaginal group crosses transversely
behind the vaginal canal between it and the anus. The deep transverse
perineal muscle is the backward continuation of the sphincter urethrae. It
appears as a triangular prolongation which passes backward deep to the
coccygeal extension of the external anal sphincter and surrounds the anal
canal. The fibers of the two sides, which originate at the junction of the
ischial and the pubic rami, are inserted into the tip of the coccyx. While both
of these muscles may have some sphincteric function, the main function of the
urogenital musculature is to support the pelvic organs. They are supplied by
the perineal nerve. Between the 2 layers of fascia the following structures are
found: the membranous urethra, the sphincter urethrae, the vagina, the internal
pudendal arteries, arteries to the bulb and the dorsal nerve to the clitoris.
In the female the greater vestibular glands (Bartholin) do not lie between the
2 layers of fascia but beneath the inferior layer so that the ducts
(bulbo-urethral glands) do not have to pierce this fascia as they do in the
male. Ischiorectal Fossa. In the urogenital half of the perineum and above
the superior layer of urogenital fascia a fat-filled ischiorectal fossa
(anterior recess) extends forward for
PELVIC DIAPHRAGM This diaphragm consists of the
levator ani and the coccygeus muscles plus the fascia which invests their
perineal and pelvic surfaces. From the pelvic wall on either side these muscles
pass downward toward the midline, where they fuse or surround the terminal
portions of the anus, the vagina and the urethra. The inferior layer of fascia
which covers this muscular diaphragm also is referred to as the anal or the
ischiorectal fascia; the superior layer is called the visceral layer of
diaphragmatic fascia. The internal pudendal artery leaves the lesser
pelvis to enter the gluteal region by passing through the lower part of the
greater sciatic foramen between the piriformis and the coccygeus muscles. After
turning around the spine of the ischium it reaches the anal part of the
perineum by passing through the lesser sciatic foramen. Then it passes along
the lateral wall of the ischiorectal fossa, where it is accompanied by its
venae comites and the pudendal nerve. In this location the artery lies in an
aponeurotic canal known as Alcock's canal. In the fossa the artery at each side
gives off the inferior hemorrhoidal artery, which passes medially through the
fatty tissue of the fossa to supply the anus and the anal canal. It also
supplies the superficial fascia, the skin of the perineum and the skin and the
musculature of the gluteal region. The main stem of the vessel continues
upward, leaves the anal triangle and enters the urogenital triangle. It
supplies the following branches: small posterior labial branches which are distributed
to the skin and the fatty tissue of the labia; the perineal artery arises
within the ischiorectal fossa, passes forward and mesialward to enter the
superficial perineal pouch by passing either over or under the perineal muscle
(within this compartment it supplies the 3 muscles of the superficial pouch,
namely, the ischiocavernosus, the bulbocavernosus and the superficial
transverse perineal); the clitoridal branch of the perineal artery enters the
deep perineal compartment by piercing the base of the urogenital diaphragm,
continues forward in the substance of the urethral sphincter muscle which it
supplies and ends in terminal branches known as the deep and the dorsal
arteries of the clitoris. These branches also supply the erectile tissue of the
superficial perineal compartment. The dorsal vein of the clitoris occupies
a groove in the medial line, with the dorsal artery and nerve lying on each
side of it; it corresponds to the deep dorsal vein of the penis. It takes
origin in the glans, passes backward and, at the root of the clitoris, passes
between the transverse ligament of the perineum and the inferior pubic
ligament; it continues upward into the pelvis to join the plexus of veins on
the wall of the vagina in the region of the neck of the bladder. Communication
is also made with the internal pudendal vein. The pudendal nerve is the
chief source of innervation to the muscles and the skin of the perineum. The
nerve on each side represents a smaller part of the pudendal plexus (the larger
part constituting the sciatic nerve). It is derived from the anterior rami of S
2, 3 and 4 and accompanies the internal pudendal artery and vein, leaving the
pelvis through the greater sciatic foramen and entering the ischiorectal fossa
through the lesser sciatic foramen. As the nerve enters the ischiorectal fossa
it gives off the inferior hemorrhoidal nerves, which accompany the
vessels of the same name medialward to supply the external sphincter ani muscle
and the skin around the anus. Near the posterior margin of the urogenital
diaphragm, the pudendal nerve divides into its two terminal branches, namely,
the perineal nerve and the dorsal nerve of the clitoris. The perineal nerve sends
superficial branches forward; they enter the superficial perineal compartment
as the posterior labial nerves. These are accompanied by the arteries of
the same name to the skin of the labia and the anterior part of the perineum.
The deep division of the nerve is muscular and supplies the muscles in the anal
and the urogenital portions of the perineum. In the anal triangle, fibers are
sent to the levator ani and the external anal sphincter; the nerve then pierces
the base of the urogenital diaphragm, enters the deep perineal compartment and
supplies the deep transverse perineal muscles and the urethral sphincter. Other
fibers supply the superficial transverse perineal, the ischiocavernosus and the
bulbocavernosus. The dorsal nerve of the clitoris enters the deep
compartment at the anterior end of Alcock's canal. It is accompanied by the
dorsal artery; it traverses this space and pierces the inferior fascia of the
urogenital diaphragm to travel forward on the dorsum of the clitoris to the
glans. It supplies the erectile tissue. The integument of the perineum has an
additional nerve supply which will be discussed with the individual nerves
appearing in this region.
ANAL TRIANGLE This triangle is bounded behind by
the coccyx, on each side by the ischial tuberosities and the sacrotuberous
ligament, which are overlapped by the lower borders of the gluteus maximus
muscles. In the midline, it contains the lower part of the anal canal and the
external sphincter ani muscle; on each side it includes the ischiorectal
fossae. Ischiorectal Fossa. Each ischiorectal fossa is prismatic in shape
and lies below the lateral part of the pelvic diaphragm. Its roof is formed by
the levator ani; the origin of that muscle from the fascia covering the
parietal pelvic muscles separates the fossa from the pelvic cavity. Its lateral
wall is formed by the lower part of the obturator internus muscle and its
fascia. In the posterior part of this wall the fascia interrupts communications
with the gluteal region through the lesser sciatic foramen. Posteriorly, the
fossa is limited by the sacrotuberous ligament; anteriorly, the base of the
perineal ligament intervenes between the fossa and the urogenital triangle. The
medial wall is formed by the anal canal and the levator ani muscle. Anteriorly,
the fossa does not end at the base of the urogenital diaphragm but continues
forward, laterally, between the urogenital and the pelvic diaphragms into the
urogenital part of the perineum. The cavity is about
SURGICAL CONSIDERATIONS
VAGINAL HYSTERECTOMY This operation is usually
done for procedentia and for prolapse of moderate degree associated with
cystocele and rectocele. Prolapse of the uterus results from a failure of the
supporting structures to hold the uterus in place. These supporting structures
are: the round ligaments, the uterosacral ligaments, the bases of the broad ligaments,
(Mackenrodt), the pelvic floor and the fascia surrounding the vagina. Vaginal
hysterectomy is performed in the following way: the lips of the cervix are
sewed together or grasped with a tenaculum for the purpose of traction. A
circular incision is made around the cervix in such a way that the bladder is
not injured. The anterior vaginal wall is freed, and the bladder is dissected
off of the anterior surface of the cervix until the vesico-uterine peritoneum
is identified. With the bladder retracted upward, the vesico-uterine peritoneum
is opened, and the index and the middle fingers of the left hand are introduced
into the peritoneal cavity. The fingers depress the fundus, and the peritoneal
opening is extended laterally on each side as far as the broad ligament. The
fundus is delivered as the fingers in the peritoneal cavity push the peritoneum
forward over the pouch of
REPAIR OF CYSTOCELE (ANTERIOR COLPORRHAPHY) The
limits of the bladder should be identified by a sound or a catheter placed in
the urethra and carried down toward the cervix. Also, the presence or the
absence of a urethrocele should be noted. Through a short transverse incision a
cleavage plane is found between the vaginal wall and the bladder. The vaginal
wall is dissected laterad on each side and separated from the underlying
musculofascial tissue; this tissue
FIG. Descent of the uterus, cystocele and rectocele. (A) Normal uterine
supports. (B) Failure of the normal uterine supports.
FIG. Vaginal hysterectomy.
is chiefly the urogenital diaphragm. The bladder
is separated from the cervix, and the pillars on each side are cut; this
permits upward displacement of the bladder. Mattress-type sutures are placed
from side to side in the tissue of the urogenital diaphragm but are placed
lateral to the urethra. With the bladder held in an upward direction, sutures
are placed through the lateral musculofascial tissue and through the uterus. In
this way, the herniation of the bladder is corrected. The redundant vaginal
flaps are trimmed and approximated with interrupted sutures.
REPAIR OF RECTOCELE (PERINEORRHAPHY) Clamps are
applied slightly within the mucocutaneous junction on each side at the
carunculae myrtiformes. Outward traction is made on the clamps, and the skin
and the mucous membrane are divided along this line. The posterior vaginal wall
is separated from the rectal wall. This dissection is carried in an upward
direction and extends above the upper margin of the rectocele. The puborectal
portions of the levator ani muscles are identified and sutured; thus, a
musculofascial bridge which keeps the herniated rectum in place is formed. The
uppermost suture grasps the undersurface of the vaginal wall. If the torn
fascia of the urogenital diaphragm is visible, this too is sutured as a
separate layer over the levator. Skin sutures are placed.
POSTERIOR COLPOTOMY This is usually used in the
treatment of pelvic abscess or as a diagnostic method in ruptured ectopic
pregnancy. Tenacula are applied to the cervix to pull it upward and
FIG. Repair of a cystocele. (A) Sagittal view of the cystocele. (B
through F) The repair.
forward, and an incision about 1 ½ inches
in length is made in the mucous membrane at the junction of the posterior
vaginal wall and the cervix. The underlying tissue is divided with scissors,
the points of which are directed toward the cervix. When the abscess cavity has
been entered, a finger is inserted to explore, and the opening is enlarged
sufficiently so that drainage may be instituted.
VESICOVAGINAL FISTULAE Birth injuries, surgery,
radium burns and carcinoma are the chief causes of such fistulae. Reich and
Wilkey have described a combined gynecologic and urologic technic to treat this
condition. The cystoscopist passes a ureteral catheter into the bladder via the
urethra and then through the fistula into the vagina. An incision is made in
the vaginal wall, and the bladder is freed. A purse-string suture is placed and
tightened simultaneously with upward withdrawal of the catheter. Reinforcing
sutures and repair complete the procedure.
RECTOVAGINAL FISTULAE These fistulae may result
from carcinoma of the cervix or the rectum, the repair of a complete perineal
laceration, and operations for abscesses and fistulae-in-ano. Smaller fistulae
above the level of the sphincter ani may be closed according to the technic of
V. C. David. A circular incision is made around the fistula, and the fistulous
tract is inverted into the rectum.
FIG. Posterior colpotomy. (A) The cervix is drawn upward, and an
incision is placed in the vaginal mucosa. (B) A sagittal section showing the
location of pus or blood in the recto-uterine cul-de-sac (
FIG. Repair of a rectocele. (A) Sagittal view of the rectocele. (B through
E) The repair.
FIG. Repair of a vesicovaginal fistula.
FIG. Repair of a rectovaginal fistula.
POSTEROLATERAL WALL
(LUMBAR OR ILIOCOSTAL REGION)
The lumbar region also has been referred to as
the iliocostal and posterolateral region of the abdominal wall. It is a
quadrilateral area situated between the lowest rib, the iliac crest, the
vertebral column and a vertical line erected at the anterior superior iliac
spine. The superficial fascia is arranged in two layers between which a large
amount of fat usually is deposited. To understand the arrangement of the
musculature in this region, reference should be made to the lumbodorsal
(lumbar) fascia.
MUSCULATURE (SUPERFICIAL, MIDDLE AND DEEP LAYERS)
The muscles of the lumbar region can be divided conveniently into 3 groups:
superficial, middle and deep. The superficial musculature consists of:
1. Latissimus dorsi 2. External abdominal oblique.
FIG. The muscles of the lumbar region in cross section at the level of
the 3rd lumbar vertebra. The serratus posterior inferior muscle is not shown in
this view.
The middle layer consists of: 1. Serratus
posterior inferior 2. Sacrospinalis (erector spinae) 3. Internal oblique muscle
The deep group consists of: 1. Quadratus lumborum 2. Psoas major 3.
Transversus abdominis. The Superficial Muscles. The latissimus dorsi arises
from the lower 6 thoracic vertebrae, from all the lumbar and upper sacral
spines and from the supraspinous ligament through the posterior layer of the
lumbodorsal fascia. It also has an origin by means of fleshy fibers from the
outer lip of the iliac crest (posterior part), the last 3 or 4 ribs, and at
times an additional origin from the inferior angle of the scapula. From this
very extensive origin the muscle inserts by means of a tendon, which is
FIG. The sacrospinalis (erector spinae) muscle. This muscle mass is
conveniently divided into 3 muscles (iliocostalis, longissimus and spinalis)
from lateral to medial. The inset shows a cross section of this group and also
of the muscles which constitute the transversus spinalis group.
FIG. The quadratus lumborum muscle. The relations of this muscle to the
iliolumbar ligament, the lumbocostal ligament and the kidney are shown.
Deep
Group of Muscles. The quadratus lumborum is a flat muscle
which lies lateral to the psoas. It arises from the iliolumbar ligament (which
extends from the 5th lumbar transverse process to the posterior part of the
iliac crest), from the adjoining part of the iliac crest and from the tips of
the lower lumbar transverse processes. It takes an upward and medial course and
becomes inserted into the lower border of the 12th rib. It fixes the last rib
so that it assists the action of the diaphragm in inspiration and bends the
vertebral column to the side. The anterior and the middle layers of lumbar
fascia surround this muscle. Its nerve supply is derived from lumbar nerves 1,
2, 3 and 4. The anterior layer of lumbodorsal fascia separates it from the
transversalis fascia. Its upper portion is strengthened anteriorly by the
lateral lumbocostal ligament. Normally, the kidney extends about
FIG. The lumbar
plexus.
FIG. The psoas muscle and sheath. (A) The psoas sheath and the course
taken by a psoas abscess. (B) Transverse section of the psoas mucle and sheath.
The
layers of the lumbodorsal fascia are shown.
FIG. Fascial relations of the kidney. (A) Cross section through the
hilus of the kidney. The renal fascia is derived from the transversalis fascia.
At the lateral border of the kidney the transversalis fascia splits into an
anterior prerenal and a posterior retrorenal layer. The fat surrounding the
kidney is arranged in 2 layers: (1) pararenal (retrorenal) fat and (2)
perirenal fat. The latter fills the space of Gerota. The arrow indicates the
lumbar approach. (B) Longitudinal section through the kidney. The 2 layers of renal fascia fuse at
the upper pole of the kidney but remain open at the lower pole. This explains
the downward path (indicated by the arrow) of a ptotic kidney and also explains
why the suprarenal remains in
situ during the course of a nephrectomy.
FIG. The kidney and its blood vessels. (A) Front view of the right
kidney. (B) When the accessory renal arteries arise from the main renal, the
phrenic or the suprarenal arteries, they are small and go to the upper pole of
the kidney. (C) When the accessory renal arteries are large, they usually are
arranged serially and go to both poles and the hilus of the kidney. (D) The
venous drainage of the dorsum of the trunk at the renal level. On the right,
the pattern is a simple one: the renal and the suprarenal veins empty directly
into the inferior vena cava. On the left the pattern is a complicated one in
which the left renal vein is the center of an extensive venous network: the
inferior phrenic and suprarenal veins enter from above. The spermatic (ovarian),
lumbar, capsular and anomalous vena cava enter from below and to the side.
Other veins which make communications are the azygos and the hemiazygos (via
the lumbars) and the internal and the external vertebral plexuses (via the
intervertebrals and the lumbars).
and the transverse processes of the lumbar
vertebrae. It arises from the 12th thoracic and all of the lumbar
vertebrae and passes downward and laterally along the margin of the pelvic
brim; it continues beneath the inguinal ligament, enters the thigh and inserts
onto a traction epiphysis of the lesser trochanter of the femur. Since this
muscle is placed deeply and medially, it does not come directly into view in
kidney surgery. It is supplied by lumbar nerves 2, 3 and 4 and is a powerful flexor
of the thigh. It also assists in medial rotation of the thigh and flexes the
trunk on the lower limb. The sheath of the psoas is a stout membranous
covering which is situated around the muscle. This sheath is attached medially
to the bodies of the lumbar vertebrae, and laterally it blends with the
anterior layer of the lumbodorsal fascia. It extends behind the femoral artery
into the thigh where it blends with the psoas tendon; above it is kept open by
its upper attachment to the body of the 2nd lumbar vertebra medially and the
1st lumbar transverse process laterally. Pus from a tuberculous thoracic
vertebra may enter the sheath and become directed into the thigh where a puffy
swelling may appear behind and on each side of the femoral vessels. Such collections
may rupture higher up into the anterior compartment of the lumbodorsal fascia
or under the iliac fascia. The transversus abdominis muscle also appears
in this region. It arises from the fusion of the 3 aponeurotic layers of
lumbodorsal fascia and extends over the anterolateral wall toward the linea
alba, where it becomes muscular. The upper part of the transversus aponeurosis
is strengthened by the posterior lumbocostal ligament. The peritoneum is
separated from this muscle by extraperitoneal fat and transversalis fascia. The
nerves which are encountered in this regions are the 12th thoracic and the
1st lumbar. The first lumbar nerve gives rise to the larger
iliohypogastric and the smaller ilio-inguinal nerves. These travel between the
psoas major and the quadratus lumborum muscles. The iliohypogastric nerve
pierces the transversus abdominis aponeurosis and then continues between it and
the internal oblique. The ilio-inguinal nerve travels along the inner surface
of the transversus aponeurosis until it perforates that muscle near the
anterior part of the iliac crest. It then pierces the internal oblique and
continues through the inguinal canal. The vessels found here are the
12th intercostal artery (subcostal) and the lumbar artery and vein. The 12th intercostal
artery is the last parietal branch of the thoracic aorta. It passes behind the
lateral arcuate ligament above the subcostal nerve and accompanies that nerve
across the quadratus lumborum and through the transversus muscle. It ends in
twigs to the transversus and the internal oblique muscles. The subcostal
vein lies above the artery, close to the last rib. Therefore, the order of
these structures is: vein, artery and nerve. The vein passes behind the lateral
arcuate ligament to join the azygos vein or the inferior hemiazygos.
KIDNEYS Fascial Relations. The surgical
anatomy of the kidneys is closely related to the lumbodorsal and the renal
fasciae. The lumbodorsal fascia consists of 3 layers – anterior, middle
and posterior – which fill the gap between the 12th rib and the iliac crest.
The posterior and the middle layers are very dense and are stronger than the
anterior. The posterior layer arises from the tips of the spines of the
lumbar, the sacral and the thoracic vertebrae; the middle layer arises
from the tips of the transverse processes of the lumbar vertebrae; and the anterior
layer arises from the anterior surfaces of the lumbar transverse processes
near their roots. The psoas fascia springs from this layer. As these 3 layers
pass laterally they fuse near the outer border of the quadratus lumborum
muscle; the fusion results in the formation of a dense tendinous structure
known as the aponeurosis of origin of the transversus abdominis muscle. It
is from this structure that the internal oblique muscle partly arises. Between
the posterior and the middle layers of lumbodorsal fascia the sacrospinalis
muscle group (erector spinae) is found, and between the middle and the anterior
layer the quadratus lumborum is situated. The renal fascia is derived from
the transversalis fascia. Tobin is of the opinion that the renal fascia is
derived from "retroperitoneal tissue." At the lateral border of the
kidney the transversalis fascia splits into an anterior (prerenal) and a
posterior (retrorenal) layer; in this way the perirenal fascial space of Gerota
is formed. The anterior layer is carried medially in front of the kidney and
its vessels, the aorta and the vena cava, and becomes continuous with its
corresponding layer of the opposite side. The posterior layer extends medially
behind the kidney and blends with the fascia of the quadratus lumborum and the
psoas major muscles. Through this layer it gains attachment to the vertebral
column. The two layers of renal fascia fuse at the upper pole of the kidney but
remain separated at the lower pole. This structural arrangement explains two
facts: (1) it is possible to shell out the kidney within its capsule, leaving
the suprarenal gland in situ, because this fascia forms a separate chamber for
the suprarenal gland, and (2) diminution of the perirenal fat predisposes to
mobility (floating) of the kidney; since the renal fascia does not fuse at the
lower pole the kidney drops caudad but does not carry the suprarenal gland with
it. The renal fascial envelope is poorly defined in the cadaver; however, like
many other fascial layers, it is quite definite in the living. G. A. G.
Mitchell is of the opinion that the anterior and the posterior layers of renal
fascia fuse superiorly and laterally. Contrary to the accepted view, he states
that they are also united medially and inferiorly. The fat surrounding the
kidney is arranged in two separate fat planes, which are: (1) the pararenal
fat (retrorenal fat) and (2) the perirenal fat. The pararenal fat is
that layer of fat which lies behind the kidney and is located between the
aponeurosis of origin of the transversus abdominis muscle and the posterior
layer of renal fascia. It varies from a small layer
FIG. Posterior relations of the kidneys, seen from behind. The deep
musculature has been removed on the right side.
pararenal fat; as they run forward, they come to
lie between the transversus abdominis and the internal oblique muscles. Both
kidneys lie above the level of the umbilicus; the right kidney reaches the
upper border of the 12th rib, the left reaches the lower border of the 11th rib
and can be placed approximately opposite the last thoracic and upper 2 lumbar
vertebrae. The right organ, as a rule, lies somewhat lower than the left
because of the volume of the right lobe of the liver. Occasionally, the kidneys
occupy the same level, and in rare instances their relations are reversed. The
long axes of the organs are not parallel but are oblique to the spine;
therefore, the upper poles are closer to each other than are the lower. The
lower poles are about
FIG. Anterior relations of the kidneys.
stomach above, the spleen laterally, the pancreas
transversely across it from the hilum to the splenic area, and the transverse
colon below; the lower pole is in contact anteriorly and medially with coils of
jejunum. It is crossed by the ascending branch of the left colic artery. Only
gastric, splenic and jejunal surfaces are covered by peritoneum. The diaphragm
separates the upper pole of the kidney from the pleura. Dorsal to the pleura
are the 12th rib and the muscles of the back. In some individuals weak spots
are left in the diaphragm above the 12th rib near its free end. The triangle is
more marked on the left side because the liver covers it on the right. If such
triangles are well developed, the lateral aspect of the kidney is in close
relation with the pleura and the last rib, being separated from them by only a
little adipose tissue. The kidneys are kept in place by attached vessels, by
the pressure of surrounding organs and by their fat and fascia. The kidneys
move downward with respiration for an excursion of about
SURGICAL
CONSIDERATIONS
NEPHRECTOMY
No single incision accomplishes the desired exposure for all conditions
affecting the kidney. Furcolo described a transfascial approach which gives
excellent exposure and produces minimal tissue damage. Another useful incision
is the one herein described for nephrectomy. The incision begins about
FIG. Various approaches to the kidney must be utilized, since no single
approach admits sufficient exposure for all surgical procedures on this organ.
The illustration shows the extraperitoneal and the transperitoneal approaches,
as well as the approach through the lumbar trigone.
The incision is carried through the skin and the
subcutaneous tissue until the musculature is exposed. The muscle layer consists
of the latissimus dorsi and the serratus posterior inferior at the posterior
end of the wound and the external oblique at the anterior extremity. The muscles
(latissimus dorsi, serratus posterior inferior, external oblique, internal
oblique and transversus abdominis) are divided until the lumbar fascia is
exposed. Deep to this fascia are the 12th dorsal nerve and vessels which cross
from above downward and forward. If possible, they should be spared. Usually a
well-developed layer of pararenal (retrorenal) fat will be found between the
lumbar aponeurosis and the retrorenal leaf of perinephric fascia. The
retrorenal leaf of renal fascia is opened and another fat layer, the perirenal
layer, comes into view. This is the surgeon's cleavage plane, since it is this
fat which immediately surrounds the kidney. This fat continues around the
pelvis, the great vessels and the ureter. The peritoneum is pushed forward as
the fat is wiped away, both poles are mobilized, and the kidney is delivered
into the wound. Nephrectomy can be accomplished after exposing and delivering
the pedicle with its contained vessels and ureter. These are clamped and
divided, the kidney is removed, and the pedicle is ligated.
NEPHROPEXY In nephropexy, Zieman has pointed out
the importance of anchoring a movable kidney along its anatomic plane.
FIG. Exposure of the left kidney.
In this way nature’s own confining fascial
covering (transversalis fascia) is utilized.
THE SUPRARENAL GLANDS These are two in number and
are situated, one on each side, in the epigastric region. They are flattened
from before backward, broad from side to side and set upon the superior
extremity of the corresponding kidney. They have separate fascial capsules;
this permits the removal of a kidney without removal of the suprarenal. For the
same reason, a suprarenal does not move with a so-called floating kidney.
However,
FIG. Nephrectomy through a lumbar approach.
VERTEBRAL COLUMN, VERTEBRAL
(SPINAL) CANAL AND SPINAL CORD
VERTEBRAL COLUMN The spinal column serves many
remarkable functions. It supports the weight of the head, acts as the central
pillar of the body, connects the upper and the lower segments of the trunk,
gives attachments to the ribs, reduces shock transmitted from various parts of
the body, forms a complete tube for the reception of the spinal cord and
permits a wide range of most complicated movements and balancing. It consists
of 33 vertebrae which are grouped according
FIG. The spinal column. (A) Posterior view; (B) anterior view; (C)
lateral view.
to region. The movable (true) vertebrae are the 7
cervical, the 12 thoracic and the 5 lumbar. The fixed (false) vertebrae are the
5 sacral, fused in adults to form the sacrum, and usually the 4 coccygeal,
fused to form the coccyx. If the bony column is examined as a whole from front
or back it seems to form a straight line, but when it is seen from the side it
presents definite curves. Viewed from the side, the vertebral column reveals 4
curvatures: the cervical and the lumbar curves are convex forward; the thoracic
and the sacrococcygeal curves are concave forward. At birth only the thoracic
and the sacral curves exist. These early thoracic and sacral curves are called
the primary curves. The secondary curves (compensatory) develop
after birth; they are the cervical and the lumbar. The cervical curve results
FIG. The
distinguishing features of the vertebrae.
from elevation and extension of the head in
infancy, and the lumbar from assumption of the erect posture when the child
begins to walk. The lumbar curve is more pronounced in women than in men and in
youth than after middle age. In the midthoracic region the tips of the spines
are below the level of the bodies of the corresponding vertebrae. The
intervertebral foramina increase in size down to the 5th lumbar vertebra. In
the sacrum they diminish from above downward. The transverse processes are in
front of the articular processes in the cervical region and in line with the
intervertebral foramina, but in the thoracic region they are behind both; in
the lumbar region they are behind the foramina but in front of the articular
processes. Viewed from in front, the bodies of the vertebrae increase in
breadth from the 2nd cervical to the 1st thoracic but diminish from the 1st
to the 4th thoracic. They increase from the 4th thoracic to the 1st
sacral, below which they reduce rapidly in size. The transverse processes of
the atlas are wide and stand out, but those of the next vertebrae are short and
nearly equal in length. Those of the 7th are long, nearly as long as
the 1st thoracic. They diminish gradually down to the 12th thoracic, where they
are represented only by tubercles. In the lumbar region they stand out again,
the 3rd being the longest. The column is widest at the sacrum,
FIG. The intervertebral disks seen in sagittal section.
FIG. The 7 cervical vertebrae.
abruptly increases at the 3rd sacral piece and
becomes greatly accentuated opposite the 5th. The vertebral column
is usually about
FIG. The effect of a protruded disk upon nerve roots. The normal is
presented for comparison.
forms the axis of rotation for the skull and the
first vertebra. The Intervertebral Disks. Between the vertebrae there is
a fibrocartilaginous disk which acts as a shock absorber. Each disk is composed
of two parts: a central nucleus pulposus, a relic of the notochord, and
an outer ring, the annulus fibrosus. The nucleus is a very elastic
semifluid tissue mass which lies more posteriorly than centrally. The annulus
forms the major part of the disk and gives form and strength to it and is the
main weight-bearing portion. Each disk is attached to the compact rim of the
superjacent and the subjacent vertebral bodies. The nucleus has been likened to
a water cushion which allows the overlying vertebrae to rock about on it, while
the strong annular fibers act as stays which prevent displacement of the
vertebral bodies. When the usual stress and strain is placed on the spinal
column the disks bulge in all directions but return to their normal positions when
the stress has been removed. They are maintained in their positions chiefly by
the anterior and the posterior longitudinal vertebral ligaments. If an unusual
strain is placed upon the vertebral column, the disk proper or its nucleus may
be extruded beyond its normal limits and fail to return to position. Posterior
protrusion may cause root pain because of pressure of the disk on one or more
of the spinal nerves; more marked protrusion may cause signs and symptoms
similar to those found in transverse lesions of the cord or the cauda equina.
These lesions have been mistaken for intraspinal neoplasms. One of the most
common locations for such a lesion is low in the lumbar region, and one of the
most common symptoms is sciatic pain. If such an abnormal protrusion is
present, it can be diagnosed by injecting Lipiodol into the subarachnoid space,
since the protruded disk will impinge on the column of radiopaque oil and will
indent or displace it. Complete obstructions to the passage of the oil have
also been observed. After the age of 60 these disks begin to atrophy, their
disappearance giving rise to the bowed back of old age. The adjacent vertebrae
articulate with each other by their bodies through the intervention of the
intervertebral disks and through their articular processes. Each
vertebra has upper and lower articular processes which are arranged for the
most part vertically, except in the cervical region where they are more
transverse. Because of these anatomic facts, it is only possible for a
vertebral dislocation without fracture to take place in the neck. Anywhere else
in the spinal column a pure dislocation cannot occur, because the articular
processes must break off before the body can be moved. The adult sacrum results
from the fusion of 5 sacral vertebrae which diminish in size from above
downward. It is triangular in shape, possessing a base or upper surface, an
apex or lower end and dorsal, pelvic and two lateral surfaces. It is divided by
paired rows of foramina on the dorsal and the pelvic surfaces into median and
lateral parts. The median portion is composed of most of the parts of the 5
fused vertebrae, and the lateral part, also called the lateral masses,
represents the fused costal and the transverse processes. These lateral masses
contain the auricular surfaces for articulation with the ilium. The laminae of
S5 and usually S4 fail to meet in the median plane; because of this, they form
the opening to the sacral canal, called the sacral hiatus. The sacral
canal contains the cauda equina, the filum terminale and the meninges down to
the middle of the 3rd sacral vertebra. At that level the meninges end, and the
lower portion of the canal contains only the nerve roots of the lower sacral
and coccygeal nerves, together with the coverings they acquire from the
meninges. The base of the sacrum is formed by the upper surface of the
VERTEBRAL (SPINAL) CANAL Together the vertebral
foramina make a continuous canal in the spinal column. The anterior wall is
closed by the posterior surfaces of the bodies of the vertebrae and their
disks; the posterior longitudinal ligament passes over these. The posterior and
the lateral walls are made up of the superimposed bony arches, the interspaces
which are covered behind by the ligamenta flava but remain open laterally as
the intervertebral foramina. It is lined entirely by ligamentous and periosteal
structures. The canal is approximately circular where it is continuous with the
foramen magnum but becomes triangular through the cervical region; it becomes
round again in the thoracic region and finally assumes a triangular form in the
lumbar region. Within the sacrum it flattens and expands laterally, and in the
flexible cervical and lumbar regions it shows distinct enlargements to
accommodate the cervical and the lumbar enlargements of the spinal cord.
FIG. The spinal meninges. Transverse section through the spinal cord and
the meninges (diagrammatic). (A) Section through a thoracic vertebra. (B)
Section through a lumbar vertebra.
Spinal
Meninges. These are 3 tubular fibrous membranes which are named
from without inward: the dura mater, the arachnoid mater and the pia mater.
They are continuous with the corresponding meninges of the brain. The space
that is situated between the dura mater and the walls of the vertebral canal is
called the epidural space; it is filled with loose areolar tissue, a
semiliquid fat, a network of veins, and small arteries to the bones. The
dura is the most complicated of the 3 membranes. It is recalled that in the
cranial cavity this membrane consists of two layers, namely, an outer layer
constituting the lining periosteum of the skull, and an inner layer which
invests the brain and by its duplications forms cranial venous sinuses. At the
foramen magnum the outer layer blends with the periosteal and the ligamentous
linings of the vertebral column, but the inner layer forms the dural sac which
invests the more delicate meninges of the cord and the emerging nerve roots.
Within the vertebral canal the dura mater forms a loose envelopelike covering
outside of the arachnoid. Although firmly connected to the 2nd and
the 3rd cervical vertebrae it is not intimately associated with the
periosteum elsewhere. It extends 5 vertebrae lower than the spinal cord proper;
it ends at the 2nd sacral vertebra with a prolongation of it investing the
filum terminale which ends at the back of the coccyx. Although firmly attached
to the 2nd and the 3rd cervical vertebrae, this covering
is loosely attached at the upper and the lower parts of the vertebral canal to
the posterior longitudinal ligament. The anterior and the posterior nerve roots
which pierce it carry tubular dural prolongations that are attached to the
periosteum of the bone at the intervertebral foramina. At the level of the 2nd
sacral vertebra where it ends, it forms a cul-de-sac which is pierced by the
filum terminale, the latter carrying its dural prolongation and becoming
attached to the coccyx. The spinal arachnoid is a thin transparent and
fragile membrane. It ends a little below the 2nd sacral vertebra;
posteriorly, it is connected to the pia mater by an incomplete posterior median
septum in the cervical region. The dura and the arachnoid move freely on one
another in the capillary interval which exists between them. The
subarachnoid space lies between the arachnoid and the pia mater and contains
FIG. A diagrammatic presentation of a section of the spinal cord and its
associated vessels and spinal nerves.
FIG. Diagrammatic
presentation of the levels of the termination of the spinal cord, the cauda
equina, the subarachnoid space and the extradural space.
the cerebrospinal fluid. It is traversed by septa
lined with flat arachnoidal cells and also by the vessels going to the brain
and the spinal cord. It communicates with the corresponding intracranial space;
therefore, an increase of pressure from hemorrhage or swelling in the brain may
be diagnosed by lumbar puncture. The pia mater in the vertebral canal is
closely applied to the spinal cord and dips into the anterior median fissure.
It is a delicate vascular membrane that is attached to the surfaces of the cord
and carries blood vessels into its substance. Along the lateral side of the
spinal cord the pia is attached to the dura by a thin membrane called the
dentate ligament. These ligaments are 20 toothlike processes which extend from
the pia to the dura; they push the arachnoid ahead of them. They leave the pia
midway between the anterior and the posterior nerve roots and serve to suspend
the cord in the midline. The lowest one of these ligaments is forked (Von
Elsberg's forked denticulation) and is placed just above the exit of the 1st
lumbar vertebra. It acts as the surgeon's guide to this nerve, giving him a
nerve root of known number from which he may determine the position of others.
The anterior and the posterior nerve roots are separated by the ligaments.
SPINAL CORD During the first days of
intra-uterine existence, a dorsal groove, the neural groove, appears on the
body surface. It becomes closed off from the neural canal, and from its walls
the central nervous system arises. Its lumen persists as the central
FIG. Development of the spinal cord.
FIG. Development of the neural arch of a vertebra around the spinal
cord.
FIG. The spinal cord and the meninges seen from behind.
spinal canal. The neural canal becomes separated
from the epidermal covering of the body by an ingrowth of mesoderm; anterior to
the canal a solid rod of cells forms known as the notochord. Around this
notochord the vertebral bodies develop. Until the 4th month of intra-uterine
life the spinal cord extends the whole length of the vertebral canal, but as
the development proceeds, owing to the greater growth of the vertebral column,
the cord extends only as far as the sacrum at the 6th month and to the lumbar
vertebra at birth. However, in adults the cord extends to the upper border of
the 2nd lumbar vertebra. The spinal cord is represented as a
cylindrical mass of nervous tissue which measures about
FIG. The spinal cord.
On each posterior root the ganglion is
found, which is composed of cells giving origin to central and peripheral
fibers. The ganglia of all except the sacral and the coccygeal nerves occupy
the intervertebral foramina. Those of the sacral and the coccygeal nerves lie
within the vertebral canal. Near the intervertebral foramen each pair of nerve
roots unites to form a spinal nerve, which divides into anterior and posterior
branches or primary divisions. Both of these divisions are mixed (sensory and
motor) nerves. Distal to the division, the spinal nerve gives off a minute
recurrent branch to the meninges and the cord, after uniting with the branch
from the sympathetic trunk. Each nerve root receives a covering from the pia
mater and one from the arachnoid before it meets the dura. Within the
subarachnoid space the roots are bathed in cerebrospinal fluid, but outside of
the space they are encased in a tubular sheath of dura which includes the
ganglion on the posterior root. The nerve fibers that constitute the white
matter are divided into two main groups: (1) the ascending and (2) the
descending. The ascending fibers are arranged in fasciculi (tracts) which
become larger as they are followed upward, because of the addition of new
fibers at each ascending level. The descending fibers form fasciculi also,
which become smaller as they are traced downward, since they are continually
giving off fibers which are intrasegmental, establishing a pathway for local
reflexes as well as connecting the gray matter at different levels. In front of
and behind the central gray matter, the anterior and the posterior commissural
fibers cross the median plane. They connect the two halves of the spinal cord
with each other, though not necessarily at the same level, while others may
join one or another of the ascending tracts after crossing the median plane.
Ascending Tracts. These
ascending fibers convey afferent impulses which may or may not be associated
with consciousness. They are divided into two groups: exteroceptive, which
receive the initial stimulus from the outside world, and proprioceptive, which
receive the initial stimuli from an internal
FIG. Cross section of the spinal cord to indicate the various spinal
tracts (diagrammatic).
source such as the muscles and the joints. It is
still uncertain whether the exteroceptive paths are 2 or
FIG. Spinal (subarachnoid) anesthesia.
and the pons to the midbrain where it ends in the
superior quadrigeminal body. Descending Tracts. These are the tracts
which pass downward through the spinal cord and are concerned with the
production of movements, both voluntary and visceral, and also form the
efferent paths for cerebellar, equilibratory, visual and other reflexes. The
cerebrospinal (pyramidal) tracts are associated with voluntary motor
impulses which travel from the cortex. The cells of origin of these fibers are
found in the cortex of the precentral gyrus and pass through the corona radiata
where they are intercepted by fibers of the corpus callosum. They enter the
posterior limb of the internal capsule and at its lower end pass as a compact
bundle into the basis pedunculi of the midbrain occupying approximately the
middle third. In the ventral part of the pons the tract is broken into a large
number of small bundles by the nuclei pontis and the transverse fibers of the
pons. In the upper part of the medulla oblongata a compact tract is
re-established and forms a surface projection on the anterior aspect called the
pyramid which lies lateral to the anterior median fissure. In the lower part of
the medulla oblongata the majority of the fibers decussate with the fibers of
the opposite side in the decussation of the pyramid and then take their final
position in the middle of the lateral right column of the spinal cord. The
lateral cerebrospinal (cross pyramidal) tract becomes smaller as it passes
downward, for it is constantly giving off fibers which terminate by arborizing
around the large motor cells in the anterior horn. The fibers of these cells
form the anterior nerve roots of the spinal nerve. Those fibers which do not
decussate in the medulla oblongata form the anterior cerebrospinal (direct
pyramidal) tract which decends in the anterior white column close to the
anterior median fissure. Before their termination these fibers also cross the
median plane and end as do the fibers of the cross tract by arborizing around
the large motor end cells of the anterior horn. As the fibers of the
cerebrospinal tract descend they give off fibers to the motor nuclei of the
cranial nerves of both sides. The vestibulospinal tract, which is the
efferent part for equilibratory reflexes, has its origin in the lateral
vestibular nucleus in the pons of the medulla oblongata. It descends near the
surface of the spinal cord in the anterior white column and terminates
uncrossed around the motor cells of the anterior horn. The rubrospinal tract
begins in the red nucleus of the midbrain. It decussates with its fellow of
the opposite side and descends through the dorsal part of the pons and the
dorsolateral part of the medulla oblongata to reach the lateral white column of
the spinal cord where it lies close to the lateral cerebral spinal tract. Its
fibers end in association with the motor cells of the anterior horn of the same
side. It is an efferent part from the cerebellum and the corpus striatum and is
concerned with the maintenance of postural tone. The tectospinal tract, together
with the ascending spinotectal tract, provides a pathway for visual reflexes
and begins in the superior corpus quadrigeminum of the midbrain. It decussates
with its fellow of the opposite side in front of the aqueduct of the midbrain.
It then passes downward in the anterior white column of the spinal cord, and
its fibers end in the same manner as those of the rubrospinal tract.
FIG. Caudal anesthesia.
ANESTHESIA Spinal (Subarachnoid) Anesthesia. This
injection produces a nerve root block. The patient may be placed in either a
lateral recumbent or a sitting position. Some surgeons, particularly Babcock,
prefer the space between the 1st and the 2nd lumbar
vertebrae. The 4th lumbar interspace is nother favorite site and is found
readily by drawing an imaginary line between the crests of the ilia. Since the
spinal cord per se ends at a higher level than the 4th interspace, there is
little danger of striking it. The selected interspace is anesthetized, and a
needle is passed through the median line. When the subarachnoid space is
entered, spinal fluid escapes upon removal of the obturator. Sacral Block
Anesthesia. Lundy includes caudal and transsacral block under the term
"sacral block anesthesia." This is extradural and reaches the nerves
within the sacral canal.
FIG.
Transsacral anesthesia.
In caudal anesthesia the needle is passed
through the sacrococcygeal ligament and into the sacral hiatus. Then the
position of the needle is changed and is passed upward along the axis of the
sacral canal for about 1 or 1 ½ inches. Then the anesthetic agent is
injected. If the needle has been placed improperly, it usually fails to enter
the sacral canal and passes superficial to the posterior aspect of the sacrum. Transsacral
anesthesia is produced by injecting about the sacral nerves via the
posterior sacral foramina. The posterosuperior iliac spine makes a good
landmark for this type of anesthesia. About