Investigation of early and late changes in a body. Forensic determination of time since death.
“The time of death is sometimes extremely important. It is a question almost invariably asked by police officers, sometimes with a touching faith in the accuracy of the estimate. Determining the time of death is extremely difficult, and accuracy is impossible”. “No problem in forensic medicine has been investigated as thoroughly as that of determining the time of death on the basis of post mortem findings. Apart from its obvious legal importance, its solution has been so elusive as to provide a constant intellectual challenge to workers in many sciences. In spite of the great effort and ingenuity expended, the results have been meagre”. (Ref. 15 at p. 33.)
“Repeated experience teaches the investigator to be wary of relying on any single observation for estimating the time of death (or “duration of the post mortem interval”), and he wisely avoids making dogmatic statements based on an isolated observation”. (Ref. 12 at p. 151.) “Considering the variables which influence the rate of body heat loss, the best one can say about the reliability of algor mortis as a post mortem clock is that it permits a rough approximation of the time of death. Errors in over-estimating and under-estimating the post mortem interval based on body cooling are common, even in the face of considerable experience by those making the estimate. Body temperature as an indicator of the post mortem interval should be correlated with all other phenomenon and observations utilised in establishing the time of death”. (Ref. 12 at p.164.)
“Formerly, it was a hallowed “rule of thumb” that the rectal temperature dropped at an average of 11/2oF per hour, rather faster during the first few hours. This method was a guarantee of inaccuracy, but little has been found to replace it. In previous editions of this book a simple calculation based on the drop in centrigrade from 37o related to a factor for environmental temperature was advocated, but further experience has shown serious errors in the method, and it is now no longer recommended”. (Ref. 8 at p. 119-120.)
“Some difference of opinion exists over the use of a thermometer at the scene of a suspicious death. Considerable caution must be employed when considering the taking of a rectal temperature with the body in situ. If there is any possibility at all of some sexual interference, whether homosexual or heterosexual, no intereference with the clothing or perineum must be made until all forensic examinations have been completed. Certainly, no instrument should be inserted into the rectum before trace evidence has been sought”. (Ref. 10 at p. 9-10.)
“Whatever method is used to calculate the estimated time since death from body temperature, all the variable factors must be taken into account to modify any basic formula, though this adjustment is very arbitrary and can only be attempted in the light of previous experience. When a “favoured” time of death is decided upon this should never be offered to the investigating authorities as a single point in time. It must be used to construct a “bracket of probability”, giving an earliest and latest time between which the doctor feels that death must have occurred.
The width of this time bracket will depend upon the number and uncertainty of the variable factors known to the doctor and is likely to be longer the more remote the death was from the time of examination of the corpse. It is futile mentioning any time in units of less than an hour, even when the death was quite recent. A medical witness who attempts to determine the time of death from temperature estimation in minutes or fractions of hours is exposing himself to a severe challenge to his expertise which may well amount to near ridicule, thus denegrating the rest of his evidence”. (Ref. 10 at p. 12.)
“The timing of the sequence of events concerned in the dissolution of the body cannot be done with accuracy and one must be cautious never to pronounce too readily that the decomposed state of the body is inconsistent with the time interval alleged”. (Ref. 6 at p. 91.)
Other words, doctors of different specialities use to rescue the peoples from death, to establish its coming, to determine a death cause, ordinary to make necropsy of dead man, and sometimes to determine time passing after coming deaths, to collide with settlement of other questions, associated with death. To can do it,it is necessary to know the bases thanatology (from greek. thanatos death + logos teaching) science, which learns a dying process, death causes till full corpse destruction, his skeletetation.
There are general and special thanatology. General thanatology learns general dying process conformities to natural laws, change, that take place in corpse, and their dependence upon the factors of external environment. Special thanatology considers properties thanatogenes attached to different illnesses (cardiac-vascular, infectious, oncologic and etc.), damages (mechanical, shouted, thermal etc.), poisoning by different poisons and other causes of death. Pick out still judicial thanatology is a part of thanatology, which belongs to the competence of judicial medicine. All types of cargo forcible and accidental, and also specific questions arising from murders investigation process, suicides and accidents are.determined.
Teaching about death in forensic medicine is in special right, because language goes about medical-juridical death fact determination bases, about remoteness setting possibility of its coming, about question of medical interference with dying process – reanimation of organism (reanimation), tissue and organ transplantation , determination of man death due to special and concrete event preceding the death (by drawing whether receipt of damages, reception of some substanses, disputtered situation etc.). A Row of questions, which arise in investigator whether judicial practice and associated with man death, caot be right solved without scientific deductions basing, done by doctor or judicially-medical expert on bases knowledges of forensic-medical thanatology. In tie from directed, some knowledges about death of man are necessary to the doctor of any speciality.
To Consider notion about death insulated from notion about life impossibly and not scientifically, because this two conformities to natural laws, that submit to inviolable dialectics law about unity and oppositions fight iature.
Thanks to active DNA founded in mummy skin, in theory one can be reproduced a full living brother-twin copy of egyptian prince “in the age” 2430 years… by reproduction without merger of sexual cells. By this method already are shown out the new sorts of agricultural plants, new breeds of domestic animals (sheep, calves) and even – monkeys. American physiologist Richard Seede from the beginning of 1998 declared, that he is ready to fall to experiments from clonning a man .
During last years in scientific and popular scientific literature appeared sizably reports, which cast light upon some questions, associated with man death. Almost told there is a fact of that what feels man in a death moment. Research work of A.Geim, R.Moudy and other confirmed, that under the short time interval, that precedes, for example, accident, to death, in conscious man intellection at first sharply accelerates and sharpens, time extraordinarily stretches, in front of internal look of that, who is dying, passes a picture of his life, consciousness bifurcates, man feels himeself outside of his own body, as if sees oneself from the side, as outsider onlooker (appears a double “symptom “). Due to the data of american researcher K.Ring , who described 102 patients cases, which were on go on to deaths, 60 % from them checked off inexpressive rest state, 37 % is dissociating from body, 23 % – flying into tunnel, 16 % light, which laid hold of them, 8 % the meetings with their relatives , which died before. Majority, that returned to life, affirmed, that “there” was better, than here.
Doctors and scientests Selstv from Gaaga and Mc Dougal from
A Lifetime of human is well known – approximately 60-80 years, rarely – more than100 years. Scientists confirmed that man life longevity depends on his genes, and also on the social factors, conditioned by social-economic state, from physical loadings, capacity, man activity etc.. Pavlov thought, that man is ought to live not less 100 years. Mechnikov showed, that rational, founded on science data, a life will shove back the death coming moment and will relieve man of fear in front of it. Man will live out a sesquipedalian saturated life and death will be by physiological phenomenon such, as sleep. In his meditations gerontology and thanatology as if flow together into one river-bed.
Prominent english learned-gerontologist Glus thinks, that man can live on a par 150-180 years, if will with proper respect behave to its life, to cling to strict plants in feeding, office hours and rest. But into over time peoples got accustomed to other lifetime, all it tempo is tuned on more short space, that’s why a long-term life seems to us fantastic.
Indisputably, that soon science will find the man life continuation methods, because research in this direction continue. For example, scientist Gering from
When man dies after 60-80 life years, death in majority is cased by the old age. Natural and unevitable end of life. But most peoples dies before, sometimes into first life (child death-rate)years, in youth and middle years. This is the premature death. It depends on amount of causes, but in general the two basic groups are showed. In one premature death is by supervention of sharp factors action of external environment, mainly physical (thermal trauma mechanical,, electro trauma, different types of mechanical asficsion, ets), rarely – chemical factors, which roughly disturb a tissue structure whether organs or their functions and organism functions as whole (different types of cargo), that bring to death,and others. In second group the factors of external environment bring in organism changes, which quickly develope and increase, for example, attached to injection illnesses, or repeating and summarizing,for example , attached to chronic heart , lungs, digestive illnesses, tumors,ets , after all also bring to violation over tissue structures whether organs, their functions, that become repugnant with life, and man dies.
Studing about death tightly interlaces with study of terminal states, border state between life and death. Into notion “terminal states” enter the hard shock (Ш–ІУ stages)forms, collaption, state, terminal pause, agony, clinical and imaginary death. By Typical peculiarity leaguing majority from them processes into terminal states, е crescent hypoxia in the tissues with the development of the acidosis by reason of accumulation of the nonoxigenated interchange products , specifically – organic acids. A Degree and duration of the acidosis specify and a reanimation prognosis.
Hard shock stages, collaption can get across immediately into preagonal state, which characterizes by braking development in higher CNS departments, to bring on consciousness loss. A preagonal state sometimes continues hours, getting across into terminal pause. It is characterizes by the lack of reflexes, momentary breathing suppression and cardiac-vascular activity. In such state man can have appearance of troupe.
Thanatology — the study of death, in all its aspects.
Dying means the transition from life to death. Such a process can be rapid or slow. If a person died rapidly, it signifies, from the point of forensic medicine, acute death. If the process of dying lasts for a long period of time, it indicates agonic death. It is so important to establish how the person died
ecause it helps to suggest a reason and cause of death. A forensic pathologist may confirm the type of dying according to the morphological features found in the body. Thus, acute death is characterized by the following: severe cadaveric staining, fluid blood in the vessels, right chambers of the heart are full of blood, subcutaneous ecchymoses, acute emphysema of lungs etc. Coagulated blood inside the body and mild cadaveric lividity are more specific for agonic death.
The process of dying passes through some stages:
1. Preagony — falling of arterial pressure, loss of consciousness, decrease of metabolism;
2. Terminal pause — arterial pressure and breathing are reduced, functioning of the central nervous centers becomes chaotic;
3. Agony — further fall of the blood pressure, cessation of breathing and a sudden return to life (the last spark of life), steep reduction of all vital functions after;
4. Somatic (Systemic or Clinical) death — is the reversible cessation of vital functions of the brain, heart and lungs. Life ceases in the body but persists in component parts, the tissues and cells.
5. Molecular (biological) death — is the death of the tissues & cells individually. It signifies the loss of life in the component parts of the body.
Relative signs of death: They are known also as immediate signs of death and may be revealed both in living (in some poisonings, electricity, severe shock etc.) and dying persons (somatic or clinical death). The following clinical findings should be determined as relative signs of death:
· passive body’s position
· pale color of the skin
· loss of reflexes and sensation
· loss of pulse and breathing
· cooling of extremities
· Byeloglazov’s sign «cat’s eye»
By Distinctive peculiarity of terminal pause there is a deep cortex braking of cerebrum attached to safety of the functions of his bulbar centres, by reason of what organism activity gets a disorganized, “chaotic” disposition. Terminal pausa continues one, sometimes 2-3 min, getting across into agony. Agony can continue from several to ЗО min and more.
Into agony period reappears breathing of convulsive type, ordinary is brushed up weak cardiac-vascular activity, reflexes and even for a little can return consciousness. Relatives often perceive such state as a sign of the beginning convalescence and liable sometimes to consider mortal end as supervention of irregular actions of medical workers.
A Transition from life to death (or dying process, that means by oneself a special organism existence method ) in time takes place unequally. In judicially-medical practice frequently it be important to set a death coming tempo of concrete man, that counts ordinary for much attached to investigation of crimes. Thats why in judicial medicine are contradistinguished the two main dying types – fast and slow, between which there can be variants.
Attached to fast dying tempo man sometimes dies instantaneously, during a some ten seconds whether a few minutes. It is a sudden death. In judicial notion medicine “sudden death”, as a rule, is connected with the diseases . However suddenly, – double-quickly, man death can come also from the influence of external factors, for example , from the head shuting wound, fall from considerable height, damaging by current etc.
From fast death differs death coming slowly, when man dies as if gradually, and composes an impression of some wrestling in the time of life. Such death is called agonic.
Agony (from greek. agonia is wrestling) can continue sometimes a few hours and even more than 24 hours. Attached to long dying in man are included all compensatory mechanisms, among them is a blood redistribution. By reason of spasm of peripheral vessels and the internal organs vessels main blood mass directs to heart and brain, that contributes to their more long exsisting. Such state of some compensation can continue during a few hours and death comes attached to the full of and unreverse exhaustion of all vital functions.
Attached to it takes place gradual relaxation of cardiac activity, develop the hypoxia phenomena of organs and tissues. Discoordinating of the blood circulating leads to the lungs oedema, brain and his capsules oedema. Gradually slows breathing, takes place obscuration of consciousness, weaken muscles, sphincters. Blood motion in the vessels stops, a skin turns pale. A face becomes earthy, nose sharped, eyeballs fall back, a cornea tarnishes its, hangs down a lower jaw ( “facies hippocratica”).
Continued agony is observed at the point of death from illnesses (specially chronic), attached to slowly crescent internal bleeding, some poisoning ets.
At the point of death with long agony in morphological troupe picture prevail the circulation of the blood discord phenomena: cyanosys, sometimes skin pallor; hypostasis in lower body departments; lungs oedema, cerebral envelopes and brain oedema; develops agonal leukocitosis and rises blood coagulation conducing to formation in heart, large vessels, sinuses of dura mater the blood packages friable,. More continued agony leads to gradual fibrin accumulation, that’s why the yellowish-white fibrynose thrombes appear . Considerable blood coagulation reverberates on degree of the cadaverous blots, because much blood is in thrombes. The cadaverous blots in such cases are weak or moderately expressed.
A second dying type characterizes by fast death coming, ordinary attached to lack of the agonal period. At the point of acute death an organism does not dip out all of its power and functional possibilities .
In parallels instance dystrophic changes of the organs, associated with long agony,are absent, but they can be present in the cerebral cells. Quick death is caused by the heart stop ( ventricle fibrillation). Sharp death is observed attached to many external influences on organism of different factors: attached to sharp anoxaemia (mechanical asphyxia, elctro damages), mechanical damages of different origin, sharp poisoning, etc.
One of morphological signs of acute death is liquid blood state in corpse.Just after the death,in all of cases blood in corpses is always liquid, exsept that places, where attached to life thrombosis was. At the point of fast death, irrespective of its causes, a blood of a dead man loses its ability to coagulate over 3-5 hours post mortem. However in such cases blood, that outpoured from man body by reason of wound, coagulates the same as and blood of living man.To bring into test-tube blood over 0,5-1 hours post mortem, the blood will coagulate, but after a while it becomes liquid again. Over 3-5 hours post mortem in people dying quickly, a blood loses ability to coagulate and thats why by the dissection of such corpses in vessels and heart cavities liquid blood is found, which does not coagulate even attached to addition of thrombine.
A liquid blood state in corpse at the point of sharp death is accounted for by supersaturating by carbonic acid and activation of plasmin.
A Liquid blood state contributes to fast formation of intensive corpse spots, in the internal organs checks off sharply expressed venous stagnation. Venous trunks, sinuses, right heart are overfulled by blood (so called asphyctic heart type ).Oedema is weakly expressed, in mucous and serose membranes small ekhimoses appears, sometimes is observed a lodge oedema of the gall-bladder, quickly develops autolis of pancreas. In internal organs microscopic sharp hypervolemia, stasis is watched, in brain capillaries stasis with perivascular effusions of blood, pericellular oedema, oedema of intermediate tissue of internal organs. In lungs sometimes there are limited effusions of blood, sharp emphysema. In rens urine is present in glomerules, in liver – expansion and filling by liquid of pericapilar spaces.
Study of pathological death physiology and different mechanisms of thanatogenesis gave a possibility to pick out two death coming periods: death somatic (clinical) and death molecular (biological).
Clinical death is such state, attached to which after breathing and heart stop is possible to renew the vital organism functions. This state as usual continues no more than 5-6 minutes . It can be more long attached to hypothermia, which is possible only in clinic conditions. On this dying stage an organism as whole does not live, however vital functions of separate tissues and organs is kept, the inconvertible changes not yet came. Reanimatology (sciences about reanimation of organism), and also transplantology (sciences about organs or tisssue transplantation )developed.
From forensic-medical point of view is important to have in mind, that under reanimation time in organism can happen the damages, which are difficultly, and sometimes and impossibly to distinguish from inlife damages.
The possibility of transplantation from troupe causes a lot of questions : determination of moment, when one can be taken transplant from a dead man (determination of the death moment), rights on corpse (permission whether prohibition, stated in precept, relative consent etc.), who from doctors sanction withdraval of organ for transplantation, etc. A lack of legislation from transplantation can bring about dramatic situations.
Biological death is such state, when the inconvertible changes in brain cortex and other organs develop and renewing of vital functions becomes impossible. For death coming moment sets a heart stop. While action of heart is kept, man lives. That’s why the heart stop is a cause of death of every man .
Death is suppression of all of vital functions.
A Individual is declared dead, when his brain does not function, and the cerebral cells do not radiate the waves, which are fixed by electroencefalograph. Blood can circulate, heart can beat, lungs can breathe, but an organism died, because consciousness is absent and after 24 silence hours in electroencephalograph scarcely will revive.
Brain Death, lack of consciousness determine individual death.
By First death sign defers a breathing stop, but it not reliable.
By Other (second) death sign defers disappearance of pulse and action stop of heart. However and this refutes by Facts of conscious control over palpitation.
Go on with you by sufficient death sign a body temperature. Are Famous the cases, when the sloping peoples long abode in cold workplaces, had a body temperature by 24°С and under this do not perish.
So-and-so, man death ascertaining ordinary lustily responsible business. Ascertaining of death is by major moment in activity of judicially-medical expert, and still major – in activity of treating doctor. Already a long while ago went the death signs determination methods searches.
There is medicolegal classification of death:
The death Signs subdivide on relative (probably, orienting or primeval) and on absolute (reliable). The death signs are divided into relative (probably, orienting or primeval) and absolute (reliable, probable).
As stated before they are the relative signs of death:
· passive body’s position
· · pale color of the skin
· · loss of reflexes and sensation
· · loss of pulse and breathing
· · cooling of extremities
· · Byeloglazov’s sign «cat’s eye»
Byeloglasovs sign, famous under name “catlike eye”. Attached to heart stop pressure in arterial system falls, by reason of what and in eyeballs a resiliency loss is marked. Attached to lateral pressing by 1-ІІ fingers on the eyeball, pupil takes oval shape reminding the pupil of catlike eye.
Byeloglasovs sign
This sign is not an absolute death sign, because can be seen attached to phenomena of sharp cardiac weakness, specifically – at the point of imaginary death, attached to cerebral comma, serious poisoning etc.
All counted signs can be observed and in living man attached to some circumstances, for example, attached to different types of the mechanical asphyksia, attached to some poisoning, cerebral shock, heat-stroke, by electric current damaging, attached to cooling of the body, epileptic attack, in state of deep unconsiousness, after strong heartfelt shocks, etc, in this case they are presented as the relative death signs.
In forensic medicine is famous such notion, as imaginary death, or fainting. It is such a man state, when for all of external signs a body looks like corpse, but actually it still lives and life glimmers in minimum dimensions (a from here latiame vita minima is a minimum life), heart beats weakly, breathing is imperceptible. Such phenomenon can bring about false ascertaining of the death.
For prevention of the mistakes, persons corpses, who died in hospitals,are send into morgue not before, than over 2 hours after coming of death, when the first cadaverous changes appear.
Absolute (reliable ) death signs are cadaverous blots and cadaverous rigor mortis, drop in body temperature to +20°С and beneath, drying out of corneas (larshe blots ) and other changes, that take place in dead body. On fact deaths indicate also the damages repugnant with life, which visibly attached to external examination (disseverance of head, dale on parts, spacious wounds worm into cavities with damage of internal organs, general body carbonizing, distinct rotting signs and т.і.). video
Into our time death of human organism from medical point of view understand in two aspects. From one side considers organism death as whole, ascertaining of final heart stop, which gives a right to doctor to say, that man died and, so, to do a suitable record in case-record and to hand a medical certificate about death. On other hand organism death considers as gradual and not simultaneous, suppression of vital functions of separate organs and cloths, in act of dying is observed cloths experience dynamics and organs.
Changes in the body
Reliable signs of death (signs of molecular death) are observed in decedents only within about 2-24 hours after death and denote molecular (biological, cellular) death. Reliable signs of death are subdivided into two groups; early (occur within 1.5-24 hours after death) and late (follow about one day and more). Medico-legal classification of post-mortem changes is listed below:
Early changes:
• cooling of the body
• post-mortem lividity (PML, Cadaveric Lividity, Post-mortem Staining, Livor Mortis)
• changes in the muscles (Cadaveric Rigidity, Rigor Mortis)
• desiccation of the skin
• autolysis
Late changes:
• preserving of the body
— saponification оr (Adipocere formation),
— mummification
• which destroy the body — putrefaction.
It is necessary to note that early changes persist in the body for 3-5 days since death but late changes — are practically unlimited (may be seen after months, years, centuries). All these changes are so important medicolegally in estimation of time since death. Other special forensic questions can be solved also on the base of morphological features in postmortem transformation of the body.
Cadaverous changes, which are by absolute death signs, – this is the processes, that develop in dead body, intensity of which depends upon amount of internal and external factors, including time.
In forensic medicine the cadaverous phenomena are divided into two groups: early ( develop during first hours post mortem) and late (or transformative), which develop usually after2-3 dayes and take place in corpse of during more-less long date, up to full his skeletation.The early changes are: troupe cooling, drying out, cadaverous blots, cadaverous rigor mortis, autolisis. The Late cadaverous phenomena are divided into destroying a corpse (rotting, troupe damaging by animals whether plants) and preserving a corpse (mummification, tanning, preservation of troupe in some environments: ice, salt solutions, petroleum ,etc.).
Early changes in the body
Many physico-chemical changes begin to take place in the body immediately or shortly after death and progress in a fairly orderly fashion until the body disintegrates. Each change has its own time factor or rate. Unfortunately, these rates of development of post mortem changes are strongly influenced by unpredictable endogenous and environmental factors. Consequently, the longer the post mortem interval, the wider is the range of estimate as to when death probably occurred. In other words, the longer the post mortem interval, the less precise is the estimate of the time of death.
ALGOR MORTIS (BODY COOLING) This is the most useful single indicator of the time of death during the first 24 hours post mortem. Some writers would regard it as the only worthwhile corporal method. It is of some importance to note that the use of body temperature estimations to assess time of death applies only to cool and temperate climates since in tropical regions there may be a minimal fall in body temperature post mortem and in some extreme climates, (e.g. central
The assessment is made on the basis of measurement of the body core temperature which, post mortem, requires a direct measurement of the intra-abdominal temperature. In practice either the temperature is measured per rectum or the intra-hepatic/sub-hepatic temperature is measured via an abdominal stab. Oral and axillary temperatures should not be used. An ordinary clinical thermometer is useless because its range is too small and the thermometer is too short. A chemical thermometer 10-12″ long with a range from 0-50o Celsius is ideal. Alternatively a thermo-couple probe may be used and this has the advantage of a digital readout or a printed record.
Whether the temperature is measured via an abdominal stab or per rectum is a matter of professional judgement in each case. If there is easy access to the rectum without the need to seriously disturb the position of the body and if there is no reason to suspect sexual assault, then the temperature can be measured per rectum. It may be necessary to make small slits in the clothing to gain access to the rectum, if the body is clothed and the garments cannot be pushed to one side. The chemical thermometer must be inserted about 3-4″ into the rectum and read in situ. The alternative is to make an abdominal stab wound after displacing or slitting any overlying clothing. The stab may be over the lower ribs and the thermometer inserted within the substance of the liver or alternatively a subcostal stab will allow insertion of the thermometer onto the undersurface of the liver.
The body temperature should be recorded as early as conveniently possible. The environmental temperature should also be recorded and a note made of the environmental conditions (see below) at the time the body was first discovered and any subsequent variation in these conditions. If a method of sequential measurement of body temperature is use then the thermometer should be left in situ during this time period.
This latter method is much easier to undertake when using a thermo-couple with an attached print-out device. Temperature readings of the body and observations made at the scene by one physician are always available for evaluation by an expert at a later time. The normal oral temperature fluctuates between 35.9oC (96.7oF) and 37.2oC (99oF). The rectal temperature is from 0.3-0.4oC (0.5o-0.75oF) higher (cited in reference 19 at p. 12). Since heat production ceases soon after death but loss of heat continues, the body cools.
During life the human body loses heat by radiation, convection, and evaporation. Heat loss by conduction is not an important factor during life, but after death it may be considerable if the body is lying on a cold surface. The fall in body temperature after death mainly depends upon a loss of heat through radiation and convection, but evaporation may be a significant factor if the body or clothing is wet. The cooling of a body is a predominantly physical process which, therefore, is predominantly determined by physical rules.
It is usually assumed that the body temperature at the time of death is normal, but in individual cases it may be subnormal or markedly raised. As well as in deaths from hypothermia, the body temperature at death may be sub-normal in cases of congestive cardiac failure, massive haemorrhage, and shock. However, the claim that severe agonal bleeding lowers the body temperature is said to be without foundation. (Ref. 10 at p. 12). The body temperature may be raised at the time of death in heat stroke, some infections, and pontine haemorrhage. Simpson (Ref. 11 at p. 7) cites a personal observation of a case of pontine haemorrhage with an initial temperature at death of 42.8oC (109oF) and another instance of a temperature of 37.4oC (99.4oF) about three hours after death in a case of manual strangulation. However, another author claims that there is no convincing proof that asphyxia by strangulation leads to a raised agonal temperature. (Ref. 10 at p. 12). Where there is a fulminating infection, e.g. septicaemia, the body temperature may continue to rise for some hours after death (Ref. 19 at p. 13). Thus the two important unknowns in assessing time of death from body temperature are (1) the actual body temperature at the time of death; and (2) the actual length of the post mortem temperature plateau. For this reason assessment of time of death from body temperature clearly cannot be accurate, (even approximately), in the first four to five hours after death when these two unknown factors have a dominant influence. Similarly, body temperature cannot be a useful guide to time of death when the cadaveric temperature approaches that of the environment. However, in the intervening period, over the linear part of the sigmoid cooling curve, any formula which involves an averaging of the temperature decline per hour may well give a reasonably reliable approximation of the time of death. It is in this limited way that the cadaveric temperature may assist in estimating the time of death in the early post mortem interval, provided the sigmoid nature of the relationship between the temperature of the cooling body and that of its environment is kept in mind.
The linear rate of post mortem cooling is affected by environmental factors and cadaveric factors other than the environmental temperature and the body temperature at the time of death. These include:
1. The “size” of the body. The greater the surface area of the body relative to its mass, the more rapid will be its cooling. Consequently, the heavier the physique and the greater the obesity of the body, the slower will be the heat loss. Some authors claim that in obese individuals the fat acts as an insulator, but for practical purposes body mass, whether from muscle mass or adipose tissue, is the most important factor. Children lose heat more quickly than adults because their surface area/mass ratio is much greater. Prominent oedema in individuals with congestive cardiac failure is said to retard cooling because of the large volume of water present with a high specific heat whilst dehydration has the opposite effect.
The effect of oedema fluid is said to be more potent than body fat. (Ref. 10 at p. 11). The exposed surface area of the body radiating heat to the environment will vary with the body position. If the body is supine and extended, only 80% of the total surface area effectively loses heat, and in the foetal position the proportion is only 60%. (Ref. 6 at p. 88).
2. Clothing and coverings. These insulate the body from the environment and therefore cooling is slower. Simpson states that cooling of a naked body is half again as fast as when clothed (Ref. 11 at p. 9). Henssge (see back of nomogram) has graded the effect of clothing by the number of layers and thickness. He states that only the clothing or covering of the lower trunk is relevant.
3. Movement and humidity of the air. Air movement accelerates cooling by promoting convection and even the slightest sustained air movement is significant. Cooling is said to be more rapid in a humid rather than dry atmosphere because moist air is a better conductor of heat. The humidity of the atmosphere will affect cooling by evaporation where the body or its clothing is wet.
4. Immersion in water. A cadaver cools more rapidly in water than in air because water is a far better conductor of heat. For a given environmental temperature, cooling in still water is about twice as fast as in air, and in flowing water, about three times as fast. Clearly the body will cool more rapidly in cold water than warm water. It has been said that bodies will cool more slowly in water containing sewage effluent or other putrefying organic matter than in fresh water or sea water. (Ref. 19 at p. 18). The author does not state whether this factor is claimed to be independent of water temperature.
Simple formulae for estimating the time of death are now regarded as naive. These include the formula of Simpson (Ref. 11 at p. 6) – “under average conditions the clothed body will cool in air at the rate of about 1.5oC an hour for the first 6 hours and average a loss of some 1oC for the first 12”. Also the formula of Camps (Ref. 5 at p. 103) – “probably the best rough estimate is afforded by the formula 98.4 minus To/1.5 = number of hours dead up to six hours, based upon skin and rectal readings, whilst corrections must be made for readings taken under the liver”. Knight devised a formula in which the fall in temperature in degrees Celsius was multiplied by a factor of 1, 11/4, 11/2, 1 3/4 or 2 for air temperatures of zero, 5, 10, 15, or 20oC respectively. His own experience with this formula has shown serious errors and he now no longer recommends it. (Ref. 8 at p. 120).
The best researched and documented method for assessing time of death from body temperature is that of Henssge (Forensic Science International 1988, Vol. 38, pp. 209- 236). This is a nomogram method rather than a formula. The nomogram corrects for any given environmental temperature. It requires the measurement of deep rectal temperature and assumes a normal temperature at death h of 3 7.2o C .
Henssge’s nomogram is based upon a formula which approximates the sigmoid shaped cooling curve. This formula has two exponential terms within it. The first constant describes the post mortem plateau and the second constant expresses the exponential drop of the temperature after the plateau according to
It is well recognised that the presence of layers of clothing, wetting of the clothing, and air movement, all influence the rate of body cooling. Similarly, bodies in still and flowing water cool more rapidly than in air. Henssge conducted experiments and derived empiric corrective factors to allow for the effect of these variables (see back of nomogram sheet which reproduces the data in his articles). In using the nomogram, Henssge emphasised “You can use right rules, but get wrong results if the points of contact are wrong. The most important thing, and – certainly – often the most difficult one, is to analyse carefully the points of contact at the scene of crime. By using the nomogram you can quickly calculate some different times since death by taking some different points of contact as a basis. This is recommended if the points of contact are not closely defined and a range of any point of contact must be taken into account”. By “point of contact” Henssge means one of the variable elements for which he has derived corrective factors. He specifically recommends “It is a good strategy to evaluate an upper and a lower limit of the mean ambient temperature which might be possible on the basis of both the ambient temperature actually measured and the probable changes of it”. And, “The choice of a corrective factor of the body weight of any case is really only an approximation. It requires personal experience. … Again it is a recommended strategy to select an upper and a lower corrective factor which might be possible”. “It must be emphasised that this method cannot be used in every case. Under some circumstances (reproduced on the back of the nomogram provided) this method must not be used because the points of contact are really unknown.”
Dessication. It starts from the places without epidermis, on mucous lips membranes and eyes. Lips are getting darker, shrivel and become more dense, hard. If eyes were open, then surface allotments of eyeball between open eyelids gradually become yellow-grey and something shrivel. If opening the eyelids, then these allotments lustily well exude like triangles, a base of which is given back to iris, and tops are to eye corners (so called Larshe blots ). These blots serve as absolute sign of actual death. They form not before 5-6 hours post mortem.
In process of time drying out takes place on that places, where skin is more thin – on fingers tips, on scrotum, on places, that exposed to pressure (without damage of skin).
Drying of the skin
If epidermis is damaged, then skin drying out places takes place double-quickly. Damaged place is getting harder and becomes dark, surface frequently uneven, ordinary few falls back in weighing with ambient skin. These allotments are difficult to cut, they are dry and more thin. Those are so called parchment blots,which can develop during life period.
LIVOR MORTIS (HYPOSTASIS, POST MORTEM LIVIDITY, POSTMORTEM SUGGILLATIONS)
Lividity is a dark purple discolouration of the skin resulting from the gravitational pooling of blood in the veins and capillary beds of the dependent parts of the body following cessation of the circulation. The process begins immediately after the circulation stops, and in a person dying slowly with circulatory failure, it may be pronounced very shortly after death.
Lividity is present in all bodies, although it may be inconspicuous in some and thus escape notice. Lividity is able to develop post mortem under the influence of gravity because the blood remains liquid rather than coagulating throughout the vascular system. Within about 30- 60 minutes of death the blood in most corpses, dead from natural or non-natural causes, becomes permanently incoagulable. This is due to the release of fibrinolysins, especially from small calibre vessels, e.g. capillaries, and from serous surfaces, e.g. the pleura.
Clots may persist when the mass of clot is too large to be liquified by the fibrinolysin available at the site of clot formation. In some deaths associated with infection and cachexia, this fibrinolytic effect may fail to develop, explaining the presence of abundant clot in the heart and large calibre vessels. Thus, in cases of sudden death the blood remains spontaneously coagulable only during a brief period immediately following death; it then becomes completely free from fibrinogen and will never again clot. This incoagulability of the blood is a commonplace observation at autopsy. The fluidity of the blood is not characteristic of any special cause or mechanism of death although many texts state that the blood remains liquid longer in asphyxial deaths. (Ref. 19 at p. 38-40). The bluish colour of post mortem lividity does not have the same connotation as cyanosis produced during life. The term “cyanosis”, which means a bluish discolouration of the skin or mucous membranes, should be confined to clinical descriptions and not used for corpses. In the living, the cyanotic colour of the blood requires the presence of at least
The medico-legal importance of post mortem lividity lies in its colour and in its distribution. The development of lividity is too variable to serve as a useful indicator of the time of death. Typically, lividity has a purple or reddish-purple colouration. Lividity in bodies exposed to the air may acquire a pink colour at the sides, but not, as rule, at the back or other areas which are close to the ground. In deaths from carbon monoxide poisoning, it is classically described as “cherry red”; in cases where methaemoglobin is formed in the blood during life (e.g. potassium chlorate, nitrates, and aniline poisoning) it appears chocolate brown; in deaths from exposure to cold, it is bright pink, and a similar colouration is seen in bodies refrigerated very soon after death. Refrigeration of a body already displaying typical purple lividity will cause it to turn pink. Similarly, lividity in parts of the body covered with moist clothes appears pink, whereas it is the usual purple colour in other areas. Cyanide poisoning results in lividity which is described by different authors as pink, bright scarlet, and violet.
Lividity is first apparent about 20-30 minutes after death as dull red patches or blotches which deepen in intensity and coalesce over the succeeding hours to form extensive areas of reddish-purple discolouration. Slight lividity may appear shortly before death in individuals with terminal circulatory failure. Conversely, the development of lividity may be delayed in persons with chronic anaemia or massive terminal haemorrhage. After about 10-12 hours the lividity becomes “fixed” and repositioning the body, e.g. from the prone to the supine position, will result in a dual pattern of lividity since the primary distribution will not fade completely. Fixation of lividity is a relative, rather than an absolute, phenomenon, but nevertheless, well developed lividity fades very slowly and only incompletely. Fading of the primary pattern of lividity and development of a secondary pattern of lividity will be quicker and more complete if the body is moved within, say, the first six hours after death, than at a later period. (Ref. 6 at p. 82). Even after 24 hours, moving the body will result in a secondary pattern of lividity developing.
Duality of the distibution of lividity is important because it shows that the body had been moved after death. However, the timing of this movement of the body is inexact. Polson (Ref. 10 at p. 14) claims “it shows that the body had been moved … within 8 to 12 hours”. Camps (Ref. 6 at p. 82) states more convincingly that “for the hypostasis of have value in this way, the body must have first remained in one position for a length of time, perhaps about 10 hours, sufficient for the lividity to have become well developed and it must then be examined early enough after being moved before much of the hypostasis has become redistributed”. The blanching of post mortem lividity by thumb pressure indicates that the lividity is not fully fixed.
Pressure of even a mild degree is sufficient to prevent gravitational filling of the vessels and this is so in the compressed areas of skin in contact with the underlying supporting surface. The result is that these compressed areas of “contact flattening” also show “contact pallor” (or “pressure pallor”). A supine corpse will display contact pallor over the shoulderblades, buttocks, calves and heels. Other areas of contact pallor will correspond with the location of firm fitting clothing, e.g. elasticated underwear, belts and collars, and any firm object lying beneath the body, e.g. the arm of the decedent. Thus, the distribution of lividity depends upon the position of the body after death.
Within intense areas of lividity, the accumulated blood may rupture small vessels to produce a scattering of punctate purple-black haemorrhages between one and several millimetres in diameter. These haemorrhages are seen most commonly over the lower legs of victims of suicidal hanging with complete suspension. These haemorrhagic loci should be distinguished from ante-mortem petechial haemorrhages. Lividity is usually well marked in the earlobes and in the fingernail beds. In a supine corpse there may be isolated areas of lividity over the front and sides of the neck resulting from incomplete emptying of superficial veins. If the head is slightly flexed on the neck, then lividity may have a linear distribution corresponding to the skin folds. (Ref. 19 at p. 36). Isolated patches of hypostasis may be due to blood in the deeper veins being squeezed, against gravity, to the skin surface by the action of muscles developing rigor mortis (Ref. 6 at p. 83).
Differentiation of lividity from bruising can be made by incising the skin. In areas of lividity the blood is confined to the dilated blood vessels whilst, in areas of bruising, the blood infiltrates the tissues and cannot be readily washed away under running tap water. Microscopic examination will resolve any doubts and provide a permanent record. In a decomposing body it may be impossible to definitively distinguish between livid staining of the tissues and a putrefying area of bruising. Areas of lividity are overtaken early in the putrefactive process. The red cells haemolyse and the haemoglobin diffuses into the surrounding tissues where it may undergo secondary changes such as sulphaemoglobin formation. In bruised areas similar putrefactive changes occur and it may be impossible to determine whether the pigment in the stained putrefied area originated from an originally intravascular or extravascular collection of blood, i.e. from a patch of congestion or from a bruise.
Lividity occurs in the viscera as well as the skin and this provides some confirmation of the external observations. In the myocardium lividity may be mistaken for an acute myocardial infarction, and in the lungs may be misdiagnosed as pneumonia. Livid coils of intestine may falsely suggest haemorrhagic infarction. Lividity developing in the viscera of a body lying prone and resulting in a purplish congestion of organs usually found pale at autopsy can be disconcerting to those unaccustomed to these changes.
Most texts agree that lividity attains its maximum intensity at around 12 hours post mortem, but there is some variation in descriptions of when it first appears, and when it is well developed. Adelson (Ref. 12 at p. 168) states that lividity “ordinarily becomes perceptible within 1/2 to 4 hours after death, is well developed within the next 3 or 4 hours, and attains its maximum degree between 8 and 12 hours post mortem”. Polson (Ref. 10 at p. 13) states that “it varies in its time of onset, is ordinarily apparent within 1/2 to 2 hours after death, and its complete development is attained in from 6 to 12 hours”. Camps (Ref. 6 at p. 81) states that it “first appears about 20-30 minutes after death as dull red patches which deepen, increase in intensity, and coalesce to form, within 6 to 10 hours, an extensive area of reddish-purple colour”. Spitz and Fisher (Ref. 14 at p. 17) state that its “formation begins immediately after death, but it may not be perceptible for as much as two hours. It is usually well developed within 4 hours and reaches a maximum beween 8 and 12 hours. … After 8 to 12 hours lividity becomes “fixed” and will remain where it originally formed”. Simpson (Ref. 11 at p. 9) states that “it commences to develop within an hour or so of death, becoming marked in 5 or 6 hours”.
Postmortem Lividity
In the stasis stage (diffusions) coagulated blood, (percolation of plasma into nearby tissues), loses former ability to shift in vessels and blot attached to pressing already does not disappear, only is getting pale and slowly proceeds in its colour.
In the stage of imbibition a cadaverous blot attached to pressing does not change its colour, the tissues are colored into violet ecquily,because of hemolysis and next imbibition of surrounding tissues with hemohlobin.
A colouring change of cadaverous blots depends not only on stage of their development, but from place and pressing force.
Muhanov A.I. offered such research methods of the cadaverous blots: pressing , taking into account pressure force, till disappearance of blot or, if it does not disappear, to lead force to
Haemoglobin changes, appearance of carboxyhemohlobin, methemohlobin cause a chocolate blood colour and lends to cadaverous blots of browny (grey) colour, etc.
Severe blood loss by reason of external whether internal bleeding can bring about that the cadaverous blots will be expressed weak or almost absent.
A Blood flows down under own weight to the bottom not only in body coverings, but in internal organs too. Specially in lungs, in bowels loops, in back stomach wall, in rens etc.
Stages of PML development
In the development of the stasis in internal organs part of plasma, which proceeds from the vessels, cumulates in pleural, abdominal and pericardial cavities. This transudation is yellow at first, and then because of haemoglobin admixtures becomes reddish. On the end of 3-4.dayes post mortem in cavities one can be found to 50-100 ml of such liquid. These changes are postmortal and are not connected with any inlife damages.
For appearance the cadaverous blots can look like bruises, that’s why it is important to distinguish them. The bruises can dispose at any body place. For exact determination it is necessary to cruciformly cut a skin in allotment of supposed bruise:accumulation of crimson liquid or coagulated blood in skin whether hypodermic cellulose indicates on bruise.
Forensic-medical meaning of cadaverous blots is significant:
1. this absolute, most early, death sign;
2. for degree of their development man can referently judge about remoteness of the coming of death;
3. they indicate on the body position post mortem;
4. on them one can be deduced about troupe position changes, about transferring of it from one place to another (to it assists a blots drawing);
An imprint of definite object on PML area
5. colouring of them gives an opportunity for the doctor to suspect a death cause ,and accordingly to plan and to take necropsy;
6. they indicate on amount whether blood state in corpse;
7. they can simulate the bruises.
RIGOR MORTIS
Ordinarily, death is followed immediately by total muscular relaxation – primary muscular flaccidity – succeeded in turn by generalised muscular stiffening – rigor mortis. After a variable period of time rigor mortis passes off spontaneously to be followed by secondary muscular flaccidity. The first investigation of rigor mortis is attributed to Nysten in 1811 (Ref. 10 at p. 15). No measurable shortening of muscle occurs during rigor mortis unless the muscles are subjected to tension. When rigor is fully developed, the joints of the body become fixed, and the state of flexion or extension of these joints depends upon the position of the trunk and limbs at the time of death. If the body is supine then the large joints of the limbs become slightly flexed during the development of rigor. The joints of the fingers and toes are often markedly flexed due to the shortening of the muscles of the forearms and legs. Since significant muscle shortening is not a normal concomitant of rigor, it is unlikely that rigor mortis would cause any significant change in the attitude adopted by the corpse at death. The view that the development of rigor mortis could produce significant movements of the body was promoted by Sommer, in about 1833, and the postulated movements became known as “Sommer’s movements”. (Ref. 10 at page 17). It is now accepted that movements of a corpse due to the development of rigor mortis can only occur in special circumstances, such as an extreme position of the body at the moment of death. If a body is moved before the onset of rigor then the joints will become fixed in the new position in which the body is placed. For this reason, when a body is found in a certain position with rigor mortis fully developed, it cannot be assumed that the deceased necessarily died in that position. Conversely, if the body is maintained by rigor in a positioot obviously associated with support of the body, then it can be concluded that the body was moved after rigor mortis had developed.
Cadaveric Regidity
Rigor involves voluntary and involuntary muscles. Rigor of the myocardium should not be mistaken for myocardial hypertrophy. Likewise secondary muscular flaccidity of the atria and ventricles should not be mistaken for ante-mortem dilatation or interpreted as evidence of myocardial dysfunction. Involvement of the iris muscles means that the state of the pupils after death is not an indication of their ante-mortem appearance. Different degrees of rigor development may give rise to irregularity and inequality of the pupils. Contraction of the arrectores pilorum muscles during rigor may result in “goose-flesh” or “cutis anserina”. The phenomenon is commonly seen in cases of drowning where it is thought to result from an agonal contraction of the muscles. Involvement of the walls of the seminal vesicles by rigor may lead to discharge of seminal fluid at the glans penis.
Rigor mortis results from a physico-chemical change in muscle protein, the precise nature of which is unknown. When the muscle tissue becomes anoxic and all oxygen dependent processes cease to function, then the level of ATP is maintained by anaerobic glycolysis which results in increasing levels of pyruvic and lactic acids. Eventually, the muscle glycogen is depleted, the cellular pH falls to around 6, and the level of ATP falls below a critical level beyond which rigor rapidly develops. Normally ATP inhibits the activation of the linkages between actin and myosin; a fall in the level of ATP allows the irreversible development of these linkages video . In individuals who have been exhausted or starved before death, the glycogen stores in muscle are low, so that rigor may develop rapidly. (Ref. 19 at p. 25). Some authors have simplified the concept of the development of rigor mortis by taking the view that a fall in the muscle pH to around 6.6 – 6.3 results in coagulation of the actinomyosin. (Ref. 12 at p. 165).
Classically, rigor is said to develop sequentially, but this is by no means constant, symmetrical or regular. Ante-mortem exertion usually causes rigor to develop first in the muscles used in the activity. Typically, rigor is first apparent in the small muscles of the eyelids, lower jaw and neck, followed by the limbs, involving first the small distal joints of the hands and feet and then the larger proximal joints of the elbows, knees and the shoulders and hips. Shapiro (Ref. 19 at p. 30), has suggested that this apparent progression through the muscles of the body reflects the fact that although rigor begins to develop simultaneously in all muscles, it completely involves small masses of muscle much more rapidly than large masses. Consequently, differences in the sizes of the joints, and in the muscles which control them, determine the development of joint fixation by rigor and produce the observed pattern of progression in the body. It is generally accepted that rigor mortis passes off in the same order in which it develops. The forcible bending of a joint against the force of rigor results in tearing of the muscles and the rigor is said to have been “broken”. Provided the rigor had been fully established, it will not reappear once broken down by force. In temperate climates rigor will typically start to disappear at about 36-48 hours after death. However, if the environmental temperature is high then the development of putrefaction may completely displace rigor within 9-12 hours of death. (Ref. 14 at p. 14). Accelerated putrefaction resulting from ante-mortem septicaemia may also lead to a rapid displacement of rigor.
There is great variation in the rate of onset and the duration of rigor mortis. Niderkorn’s (1872) observations on 113 bodies provides the main reference database for the development of rigor mortis and is commonly cited in textbooks. His data was as follows (Ref. 19 at p. 31):
Number of Cases Hours Post Mortem at which Rigor was Complete.
In this series, rigor was complete in 14% of cases at 3 hours post mortem and this percentage had risen to 72% at 6 hours and to 90% at 9 hours. By 12 hours post mortem rigor was complete in 98% of cases. (Note that this data is presented in a somewhat confusing way in Ref. 10 at p. 15). Against the background of this data it can be readily appreciated that the generally quoted rule of thumb that rigor commences in 6 hours, takes another 6 to become fully established, remains for 12 hours and passes off during the succeeding 12 hours, is quite misleading.
The intensity of rigor mortis depends upon the decedent’s muscular development; consequently, the intensity of rigor should not be confused with its degree of development. In examining a body both the degree (complete, partial, or absent) and distribution of rigor should be assessed after establishing that no artefact has been introduced by previous manipulation of the body by other observers. Attempted flexion of the different joints will indicate the amount and location of rigor. As a general rule when the onset of rigor is rapid, then its duration is relatively short. The two main factors which influence the onset and duration of rigor are (a) the environmental temperature, and (b) the degree of muscular activity before death. Onset of rigor is accelerated and its duration shortened when the environmental temperature is high. If the temperature is below 10oC it is said to be exceptional for rigor mortis to develop, but if the environmental temperature is then raised, rigor mortis is said to develop in a normal manner. (Ref. 19 at p. 31). Rigor mortis is rapid in onset and of short duration after prolonged muscular activity, e.g. after exhaustion in battle, and following convulsions.
Conversely, a late onset of rigor in many sudden deaths might be explained by the lack of muscular activity immediately prior to death.
In addition to these two principal factors, other endogenous and environmental factors are claimed to influence the onset of rigor. Onset is relatively more rapid in children and the aged than in muscular young adults. It develops early and passes quickly in deaths from septicaemia or from wasting diseases. It is delayed in asphyxial deaths, notably by hanging or carbon monoxide poisoning, and also when death has been immediately preceded by severe haemorrhage. (Ref. 10 at p. 15). The opinion of Knight that “it is extremely unsafe to use rigor at all in the estimation of time since death” is somewhat extreme. (Ref. 8 at p. 123.) However, the rule of thumb offered by Camps is overly simplistic – “corpses can usually be divided into those, still warm, in which no rigor is present, indicating death within about the previous three hours. Those in which rigor is progressing, where death probably occurred between 2 and 9 hours previously; and those in which rigor is fully established, showing that death took place more than 9 hours previously”. (Ref. 6 at p. 85). Knight states that “the only possible use is in the period around the second day, when body temperature may have dropped to environmental but putrefaction has not yet occurred. If full rigor is present, then one might assume that this is about the second day following death, depending upon the environmental conditions”. (Ref. 8 at p. 123).
Exposure of a body to intense heat results in heat stiffening due to coagulation of the muscle proteins. Unlike rigor mortis, heat stiffening is associated with muscle shortening resulting in the characteristic pugilistic posture of burned bodies. Heat stiffening obscures rigor mortis with which it should not be confused. Freezing of a body will cause stiffening of the muscles, postponing the development of rigor which is said to develop as soon as thawing of the body permits.
Cadaveric spasm (synonyms: instantaneous rigor, instantaneous rigidity, cataleptic rigidity) is a form of muscular stiffening which occurs at the moment of death and which persists into the period of rigor mortis. Its cause is unknown but it is usually associated with violent deaths in circumstances of intense emotion. It has medico-legal importance because it records the last act of life. Cadaveric spasm may affect all the muscles of the body but it most commonly involves groups of muscles only, such as the muscles of the forearms and hands. Should an object be held in the hand, then cadaveric spasm should only be diagnosed if the object is firmly held and considerable force is required to break the grip.
Cadaveric spasm involving all the muscles of the body is exceedingly rare and most often described in battle situations. (Ref. 6 at p. 85, and Ref. 10 at p. 19). Cadaveric spasm is seen in a small proportion of suicidal deaths from firearms, incised wounds, and stab wounds, when the weapon is firmly grasped in the hand at the moment of death. In such circumstances the gripping of the weapon creates a presumption of selfinfliction of the injuries. This state cannot be reproduced after death by placing a weapon in the hands. It is also seen in cases of drowning when grass, weeds, or other materials are clutched by the deceased. In this circumstance, it provides proof of life at the time of entry into the water. Similarly, in mountain fatalities, branches of shrubs or trees may be seized. In some homicides, hair or clothing of the assailant may be found in the hands of the deceased.
Cataleptic (from greek. katalepsis is grip) cadaverous rigor mortis comes immediately post mortem. It is observed at the point of death from damage of oblong brain, effusion of blood into oblong part of brain etc. In that case body fixs in that pose, in which it died.
Contradistinguish general cataleptic rigor mortis and local cataleptic rigor mortis.
There is also thermal rigor mortis, which develops attached to temperature of ambient environment above 50°С by reason of muscle protein coagulation. It arises attached to being borrowed of troupe into flame and does not depend on time.
Forensic-medical sense of the rigor mortis is hudge:
1. this is absolute early death sign;
2. it helps to define approximate death coming remoteness (for degree of his development );
3. rigor Fixs a troupe pose post mortem;
4. it gave a possibility sometimes to judge about transferring of troupe from one place into other (with pose change );
5. it can lend a hand in recognition of death cause and its genesis ;
6. rigor mortis of the smooth muscle fibres of internal organs can imitate the inlife sickly states .
Autolysis. This is a process of self-digestion of tissues, caused by the action of proteolytic enzymes. As a rule, autolysis may be found in organs with great volume of proteolytic enzymes (stomach, pancreas, adrenal glands). Its forensic importance is insignificant.
In stomach takes place selfdigestion of mucous envelope, softening of stomach wall up to its break. The Identical changes can be by mistake adopted for action of caustic poisons.
Quickly develops autholisis in bowels, pancreas -it strikes prettily fast full autholisis, sometimes with hemorrage and can be wrongly considered as sharp hemoragic necrosis.
In the adrenal glands double-quickly disintegrates a cerebral matter. About posthumous process properties testifies a lack of cultural reaction on cloths death.
In forensic medicine autholisis is iegative right, because it prevents the correct diagnostics of the inlife changes.
Late changes in the body
Putrefaction. It is the last stage in the resolution of the body from the organic to the inorganic state; and is produced mainly by the action of bacterial enzymes, mostly anaerobic organisms derived from the bowel. They produce a multitude of enzymes which break down the various tissues of the body. Certain factors as warmth, moisture or air, which favor bacterial growth, accelerate the onset and progress of putrefaction. Microorganisms responsible for putrefaction are: Streptococci, Bacteroides, Proteus, B. Coli, Clostridium Welchii. C. Welchii, produces lecithinase, which hydrolyses the lecithin in cell membranes, including blood cells, and is responsible for hemolysis and initiating the putrefactive process. The other microorganisms mentioned above, produce a large number of enzymes which break down human tissue. Characteristic features of putrefaction:
· Color changes
· Gas production
· Pressure effects of putrefactive gases
The first sign of putrefaction is a bad smell which is noticed within 20-30 hours after death. First color changes can be seen at the right iliac fossa in 2-3 days after death. The skin at this site becomes greenish. It is explained by the following: the bowel, at the above mentioned area, is more liquid and full of bacteria. The microorganisms in the bowels produce hydrogen sulphide, which reacts with the haemoglobin liberated from the haemolysed blood cells due to bacterial action, resulting in the formation of sulph-met-haemoglobin. Later, 4-5 days after death, the green coloration spreads over the entire abdomen, genitals, extremities, face etc. video The whole body of the deceased is discolored within approximately 1-2 weeks.
Gases collect in the intestines in 3 to 5 days, and the abdomen becomes tense and distended. Due to this, the diaphragm is forced upwards, compressing the lungs and heart. Blood-stained froth exudes from the mouth and nostrils (post-mortem purge). The compression of the stomach by the gases may force food outside (post-mortem vomit). Sometimes, the great pressure of gases results in post-mortem delivery of a fetus. When 5-7 days have elapsed after death the subcutaneous tissues become emphysematous and even a thin body appears obese (cadaveric emphysema is formed). The gas formation in the blood vessels may force blood stained fluid, air or liquid fat to form small blisters between the epidermis and dermis. These gradually enlarge, unite and rupture, exposing large areas of dermis (post-mortem bubbles). It takes place during 1,5-2 weeks after death.
Putrefaction is the post mortem destruction of the soft tissues of the body by the action of bacteria and enzymes (both bacterial and endogenous). Tissue breakdown resulting from the action of endogenous enzymes alone is known as autolysis. Putrefaction results in the gradual dissolution of the tissues into gases, liquids and salts. The main changes which can be recognised in the tissues undergoing putrefaction are changes in colour, the evolution of gases, and liquefaction.
Bacteria are essential to putrefaction and commensal bacteria soon invade the tissues after death. The organisms most commonly found are those normally present in the respiratory and intestinal tracts, namely anaerobic spore-bearing bacilli, coliform organisms, micrococci, diphtheroids and proteus organisms. The marked increase in hydrogen-ion concentration and the rapid loss of oxygen in the tissues after death favour the growth of anaerobic organisms. (Ref. 19 at p. 43). The majority of the bacteria come from the bowel and Clostridium welchii predominates. Any ante-mortem bacterial infection of the body, particularly scepticaemia, will hasten the onset and evolution of putrefaction. Environmental temperature has a very great influence on the rate of development of putrefaction so that rapid cooling of the body following a sudden death will markedly delay its onset. In the temperate climate of the
Putrefaction is optimal at temperatures ranging between 70-100oF (21-38oC) and is retarded when the temperature falls below 50oF (10oC) or when it exceeds 100oF (38oC). (Ref. 10 at p. 20). The rate of putrefaction is influenced by the bodily habitus of the decedent; obese individuals putrefy more rapidly than those who are lean. Putrefaction will be delayed in deaths from exsanguination because blood provides a channel for the spread of putrefactive organisms within the body. Conversely, putrefaction is more rapid in persons dying with widespread infection, congestive cardiac failure or anasarca. Putrefaction is accelerated when the tissues are oedematous, e.g. in deaths from congestive cardiac failure, and delayed when the tissues are dehydrated. It tends to be more rapid in children than in adults, but the onset is relatively slow in unfed new-born infants because of the lack of commensal bacteria. Whereas warm temperatures enhance putrefaction, intense heat produces “heat fixation” of tissues and inactivates autolytic enzymes with a resultant delay in the onset and course of decomposition. Heavy clothing and other coverings, by retaining body heat, will speed up putrefaction. Rapid putrefactive changes may been seen in corpses left in a room which is well heated, or in a bed with an electric blanket. Injuries to the body surface promote putrefaction by providing portals of entry for bacteria and the associated blood provides an excellent medium for bacterial growth.
After normal burial, the rate at which the body decomposes will depend to a large extent on the depth of the grave, the warmth of the soil, the efficiency of the drainage, and the permeability of the coffin. The restriction of air, in deep burials, particularly in clay soil, will retard decomposition, but never prevent it altogether. Buried in well drained soil, an adult body is reduced to a skeleton in about 10 years, and a child’s body in about 5 years. (Ref. 6 at p. 91). Immersion of the body in faeces-contaminated water, such as sewage effluent will enhance putrefaction; however, it is generally accepted that in the first 48 hours after death changes are in the main due to organisms already present in the body. (Ref. 5 at p. 105). According to an old rule of thumb (
Typically, the first visible sign of putrefaction is a greenish discolouration of the skin of the anterior abdominal wall. This most commonly begins in the right iliac fossa, i.e. over the area of the caecum, (where the contents of the bowel are more fluid and full of bacteria), but occasionally, the first changes are peri-umbilical, or in the left iliac fossa.
The discolouration, due to sulph-haemoglobin formation, spreads to involve the entire anterior abdominal wall, and then the flanks, chest, limbs and face. As this colour change evolves, the superficial veins of the skin become visible as a purple-browetwork of arborescent markings, which tend to be most prominent around the shoulders and upper chest, abdomen and groins. This change, owing to its characteristic appearance, is often described as “marbling”. The skin, which now has a glistening, dusky, reddish-green to purple-black appearance, displays slippage of large sheets of epidermis after any light contact with the body, e.g. during its removal from the scene of death. Beneath the shed epidermis is a shiny, moist, pink base which dries, if environmental conditions permit, to give a yellow parchmented appearance. This putrefactive “skin-slip” superficially resembles ante-mortem abrasions and scalds. Indeed, post mortem scalding of a body with water at 65oC (149oF) produces skin slip of the same type as in putrefaction. (Ref. 6 at p. 89).
Subsequently, skin blisters varying in size from less than
The dusky, greenish-purple face appears bloated with the eyelids swollen and tightly closed, the lips swollen and pouting, the cheeks puffed out, and the distended tongue protruding from the mouth. The head hair and other body hair is loose at its roots and can be easily pulled out in large clumps. The finger and toenails detach, often with large sheets of contiguous epidermis forming complete “gloves” or “socks” – a process described as “degloving”. The neck, trunk and limbs are massively swollen, giving a false impression of gross obesity. Finally, the putrid gases, which are under considerable pressure, find an escape and the whole mass of decomposing soft tissues collapses.
Putrefaction progresses internally beginning with the stomach and intestine. The gastric mucosa and the intestines are discoloured a brownish-purple. The mucosa of the airways is a deep red and there is haemolytic plum-coloured staining of the endocardium and the vascular intima which is most readily appreciated in the aorta and its major branches. Small white granules – so-called “miliary plaques” – are seen rarely over the endocardium and epicardium. (Ref. 10 at p. 22). The heart becomes flabby, the wall thinned, and the myocardium a deep dirty red. A similar discolouration is seen in the liver and kidneys.
The spleen becomes mushy and friable. The liver develops a honey-comb pattern resulting from gas formation and similar changes may be seen in the brain, most readily if it is fixed in formaldehyde prior to cutting. Subsequently the brain becomes semiliquid.
The lungs, loaded with sanguinous fluid, appear dark red and are friable. Gradually a great part of this sanguinous fluid is lost by diffusion into the pleural cavities.
Diffusion of bile pigments from the gall bladder discolours the adjacent liver, duodenum and transverse colon. The capsules of the liver, spleen and kidneys resist putrefaction longer than their parenchymatous tissues with the result that these organs are often converted into bags of thick, turbid, diffluent material. Progression of decomposition is associated with organ shrinkage.
The more dense fibro-muscular organs such as the prostate and uterus remain recognisable until late in the process, thus aiding in the identification of sex.
Perforation of the fundus of the stomach or lower oesophagus into the left pleural cavity or the abdomen may occur within a few hours of death. This is the result of autolysis rather than bacterial putrefaction. An uncommon finding, it is most frequently associated with cerebral injuries and terminal pyrexias. (Ref. 14 at p. 19). It is occasionally characterised as “neurogenic perforation of the oesophagus”.
There is considerable variation in the time of onset and the rate of progression of putrefaction. As a general rule, when the onset of putrefaction is rapid then the progress is accelerated. Under average conditions in a temperate climate the earliest putrefactive changes involving the anterior abdominal wall occur between 36 and 72 hours after death. Progression to gas formation occurs after about one week. The temperature of the body after death is the most important factor generally determining the rate of putrefaction. If it is maintained above 26oC (80oF) after death then putrefactive changes become obvious within 24 hours and gas formation will be seen in about 2-3 days. (Ref. 6 at p. 91).
The putrefactive changes which have taken place up to this time are relatively rapid when contrasted with the terminal decay of the body. When the putrefactive juices have drained away and the soft tissues have shrunk, the speed of decay is appreciably reduced.
The Late cadaverous phenomena begin to develop though just post mortem, but become distinct more frequent on 2-3 day, full of development to reach considerably later (on the strength of a little weeks, months and even years). They bring on considerable troupe changes (his semblance, organs bilding and cloths).
The Late cadaverous phenomena are destroying (exterminatory) and preventive a corpse. To destroying bear away rotting, destruction of troupe by animals and plants; to preserving – mummification, fatty-wax, peat tanning, preservation of troupe in concentrated salt solutions, in ice and other environments (petroleum, tar and т.і.).
Destruction of the corpse by animals and plants. The peoples Corpses can expose to damages by insects, domestic and wild animals, plants.
The Insects settle on corpse before long after coming of death and quickly propagate (into summery period). First on corpse into warm year time settle flies, which oviposit. The Larvas, that appear from them, worm into corpse, into internal organs, up to brain, and begin its destroying work. Amount of larvas can be enormous. In skin they make the holes, which can be adopted for shallow chipped whether fractional wounds. The Larvas bear down internal organs and all of soft cloths. . Attached to favourable conditions the flies larvas can eat a child corpse to bone for 1,5-2 weeks, and corpse of adult – for 1-1,5 months.
Exclusive of flies, corpse can destroy other insects and spineless. Ants over 4-8 weeks can transform a corpse into skeleton. Prettily quickly begin eat a corpse cockroaches, forming allotments like of parchment blots, which sometimes take for scratch whether guardianship.
By troupe Fauna, her remainders (larvas, dollies) one can be been guided attached to determination of death coming remoteness.
Vertebrates also can destroy a corpse. Eating up of corpses by hungry hyaenas, foxes, wolves, jackals.
Mise and specially rats can considerably eat soft parts of troupe, into first turn are open body allotments: faces and arms. Attached to stay of troupe in reservoir can have a damage place by river whether sea animals: by watery beetles, leeches, starfishes, some fishes.
Forensic-medical damages sense from animals consists in that they can be adopted for inlife damages, and main – destroy the damages peculiarities being attached to life.
On peoples corpses can settle the different plants.First of all we should indicate on mould covering . A Mould settles on dress, skin, and germinates into more deep layers of the epidermis.
Corpse, that is found in the open, fleetly in earth can germinate by plants (specifically – by grasses), their roots and trees roots.
Almost always late changes begin from rotting, which in some stage on the strength of conditions inauspicious for it can cease, and corpse begins preserve. That’s why distantly not always iatural conditions the corpses are preserving fully.
Mummification. Mummification is a modification of the putrefaction in which there is dehydration or total dessication of the body video. The skin becomes dry, shrunken, leathery and rusty brown. The body is odorless. The soft parts shrivel up, but retain their natural appearances and features. Internal organs become a dried mass. Free circulation of air, high temperature and the absence of moisture are the main factors affecting mummification. Required time for mummification is around 2-3 months (in the conditions mentioned above) video.
Mummification is a modification of putrefaction characterised by the dehydration or dessication of the tissues. The body shrivels and is converted into a leathery or parchment-like mass of skin and tendons surrounding the bone. The internal organs are often decomposed but may be preserved. Skin shrinkage may produce large artefactual splits mimmicking injuries. These are particularly seen in the groins, around the neck, and the armpits. (Ref. 14 at p. 23).
Mummification develops in conditions of dry heat, especially when there are air currents, e.g. in a desert or inside a chimney. New-born infants, being small and sterile, commonly mummify. Mummification of bodies of adults in temperate climates is unusual unless associated with forced air heating in buildings or other man-made favourable conditions.
The forensic importance of mummification lies primarily in the preservation of tissues which aids in personal identification and the recognition of injuries. The time required for complete mummification of a body cannot be precisely stated, but in ideal conditions mummification may be well advanced by the end of a few weeks.
Medico-legal importance of Mummification:
· It indicates time elapsed since death
· It may indicate the cause of death
· It helps to identify a person
· It indicates the burial site
Mummification
Mummification can be general, to spread on all corpse, and partial, when dry out only separate parts of body; natural and artificial. A Raised temperature considerably hastens mummification, because assists moisture to coming out and halts rotting. That’s why mummification often meets in localities with hot climate. However possible mummification and attached to more low temperature, if only found kind change of dry air.The lesser troupe mass, so much the better and quicker it dries out.
Attached to mummification a corpse gradually begins shrivel, indurates and becomes darker, a skin acquires properties of the pergament. Sharply falls weight of dead body, and it diminishes in volume. A weight Loss can be 75-90%. The Soft tissues become crumble, sometimes collapse by clothes-moth, ticks, can transform into powder. Time, necessary for mummification, usually calculates by months. Attached to favourable conditions a corpse of adult can mummify for 2-3 months, and child – still before .
A Person of mummified corpses ordinary is easily recognised , but a death date in these cases to define almost impossibly.
Saponification (Adipocere formation). It is a modification of the putrefactive process in which the fatty tissues of the body are hydrolyzed into fatty acids. Adipocere (adipis > soft fat, cera > wax). Saponification is usually first seen in bone marrow and the subcutaneous fat of cheeks, breasts, buttocks and abdomen. It is a yellowish white, greasy wax-like substance with a rancid smell. Its density is less than water, that’s why adipocere floats on water. It is composed of saturated fatty acids (stearic, palmitic), calcium soaps, proteins etc. and in result from hydrogenation of unsaturated body fats into firmer fats and their hydrolysis into fatty acids. It cuts easily and burns with a faint yellow flame. The time required for adipocere formation is around 8-10 months (for the Ukrainian climate).
Saponification or adipocere formation is a modification of putrefaction characterised by the transformation of fatty tissues into a yellowish-white, greasy, (but friable when dry), wax-like substance, with a sweetish rancid odour. Mant states that when its formation is complete it has a sweetish smell, but during the early stages of its production a penetrating ammoniacal odour is emitted and the smell is very persistent. (Ref. 9 at p. 25). It floats on water, and dissolves in hot alcohol and ether. When heated it melts and then burns with a yellow flame. Ordinarily it will remain unchanged for years.
Adipocere develops as the result of hydrolysis of fat with the release of fatty acids which, being acidic, then inhibit putrefactive bacteria. The low (0.5%) level of free fatty acids in fat at the time of death may rise to 70% or more by the time adipocere is obvious to the naked eye. (Ref. 6 at p. 93). However, fat and water alone do not produce adipocere. Putrefactive organisms, of which Clostridium welchii is most active, are important, and aipocere formation is facilitated by post mortem invasion of the tissues by endogenous bacteria. A warm, moist, anaerobic environment thus favours adipocere formation. It was once thought that adipocere required immersion in water or damp conditions for its development. However, the water content of a body may be sufficient in itself to induce adipocere formation in corpses buried in well sealed coffins. (Ref. 9 at p. 27).
Adipocere develops first in the subcutaneous tissues, most commonly involving the cheeks, breasts and buttocks. Rarely, it may involve the viscera such as the liver. (Ref. 6 at p. 93). The adipocere is admixed with the mummified remains of muscles, fibrous tissues and nerves. The final product is of a larger bulk than the original fat with the result that external wounds may become closed and the pattern of clothing or ligatures may be imprinted on the body surface.
Under ideal warm, damp conditions, adipocere may be apparent to the naked eye after 3- 4 weeks. (Ref. 9 at p. 27 and Ref. 12 at p. 175). Ordinarily, adipocere formation requires some months and extensive adipocere is usually not seen before 5 or 6 months after death. (Ref. 14 at p. 23). Other authors suggest that extensive changes require not less than a year after submersion, or upwards of three years after burial. (Ref. 10 at p. 25). The medico-legal importance of adipocere lies not in establishing time of death but rather in its ability to preserve the body to an extent which can aid in personal identification and the recognition of injuries. The presence of adipocere indicates that the post mortem interval is at least weeks and probably several months.
Medico-legal importance of Saponification:
· It indicates time elapsed since death
· It may indicate the cause of death
· It helps to identify a person
A Process of tanning is learned insufficiently.
MACERATION
Maceration is the aseptic autolysis of a foetus which has died in utero and remained enclosed within the amniotic sac. Bacterial putrefaction plays no role in the process. The changes of maceration are only seen when a still-born foetus has been dead for several days before delivery. Normally the changes take about one week to develop. (Ref. 10 at p. 31 and Ref. 19 at p. 54).
Examination of the body needs to be prompt since bacterial putrefaction will begin following delivery. The body is extremely flaccid with a flattened head and undue mobility of the skull. The limbs may be readily separated from the body. There are large moist skin bullae which rupture to disclose a reddish-brown surface denuded of epidermis. Skin slip discloses similar underlying discolouration. The body has a rancid odour but there is no gas formation.
VITREOUS HUMOUR POTASSIUM
The relationship between the rise of potassium concentration in the vitreous humour and the time since death has been studied by several workers and recently reviewed by Madea et al. An obstacle to using potassium concentration in vitreous humour as an aid in estimating the time since death are the different 95% confidence limits given by different authors. Up to 100 hours post mortem, the 95% confidence limits of different authors vary between ± 9.5 hours up to ± 40 hours; in the early post mortem interval up to 24 hours, the 95% confidence limits of different authors varies from ± 6 hours up to ± 12 hours. There are also sampling problems in that the potassium concentration may differ significantly between the left and right eye at the same moment in time. Simultaneous sampling of both eyes has shown that the potassium concentration in one eye can deviate by up to 10% from the mean value of both eyes. In order to improve the accuracy of the method cases with possible ante-mortem electrolyte disturbances can be excluded by eliminating all cases with a vitreous urea above an arbitrary level of 100 mg/dl. (High urea values in vitreous humour always reflect ante-mortem retention and are not due to post mortem changes). Having eliminated these cases with possible ante-mortem electrolyte imbalance, there is a linear relationship between potassium concentration and time after death up to 120 hours, but the 95% confidence limits are ± 22 hours
Forensic diagnostics of time since death.
A recurring problem in forensic medicine is the need to fix the time of death within the limits of probability. It is self-evident that the longer the interval of time between death and the examination of the body, the wider will be the limits of probability. The longer the post mortem interval, the more likely it is that associated or environmental evidence will furnish more reliable data on which to estimate the time of death than will anatomical changes. It is necessary to be alert to the possibility that the post mortem interval (the time elapsed from death until discovery and medical examination of the body) may be preceded by a significant survival period (the time from injury or onset of the terminal illess to death). The survival interval is best established by evaluating the types, severity and number of injuries present and the deceased’s response to them, taking into account pre-existing natural disease. At autopsy it is necessary to assess the evolution of the inflammatory response and repair process in skin and viscera.
Establishing the times of an assault and death has a direct bearing on the legal questions of alibi and opportunity. If the suspect is able to prove that he was at some other place when the fatal injury was inflicted then he has an alibi and his innocence is implicit. Conversely, if the time of a lethal assault coincides with the time when the suspect was known to be in the vicinity of the victim, then the suspect clearly had an opportunity to commit the crime. In cases of infanticide, it is necessary for the prosecution to establish that the child was born alive and was killed afterwards. In the absence of proof that death occurred after a live birth, there can be no prosecution for infanticide. Similarly, in bodies recovered from fires, it is critical to establish whether death occurred before or during the fire and this necessitates correlating information relevant to establishing both the time of death and the cause of death. When a body is recovered from water, a critical question is whether the person was alive or dead when they entered the water. Determining whether specific injuries were inflicted before or after death is another important example of establishing temporal relationships.
Sources of Evidence
Evidence for estimating the time of death may come from three sources:
1. Corporal evidence, i.e. that present in the body.
2. Environmental and associated evidence, i.e. that present in the vicinity of the body,
3. Anamnestic evidence, i.e. that based on the deceased’s ordinary habits, movements, and day to day activities.
All three sources of evidence should be explored and assessed before offering an opinion on
when death or a fatal injury occurred.
There are two methods for estimating the time of death:
1. The rate method. Measuring the change produced by a process which takes place at a known rate which was either initiated or stopped by the event under investigation, i.e. death. Examples include the amount and distribution of rigor mortis, the change in body temperature, and the degree of putrefaction of the body.
2. The concurrence method. Comparing the occurrence of events which took place at known times with the time of occurrence of the event under investigation, i.e. death. For example, a wrist watch stopped by a blow during an assault, the extent of digestion of the last known meal.
Post-mortem Interval. It is the time between death and the examination of the body. It is very important for the investigator to know when the crime was committed video . Because there are numerous and considerable biological variations in every individual cases, The exact time of death cannot be fixed by any methods, but only an approximate range of the time can be given. Generally, the time since death can be calculated according to the followings:
Body Cooling .
The rate of cooling is not uniform but is almost proportional to the d/f in temperature between the body and surroundings. Average heat loss is roughly 1°С per hour and the body attains environmental temperature in about 16-20 hours after death.
Post-mortem Lividity. It begins as mottled patches within 1-3 hours. These patches increase in size, coalesce in 3-6 hours when the lividity is fully developed and fixed in about 6-12 hours. Despite any stage of its development, it has a definite duration.
Rigor Mortis. It commences 2-3 hours after death, develops in 8-12 hours, persists for 2-3 days, and passes off 3-4 days after death.
Decomposition Changes. Bad odor is noticed after 20-30 hours have elapsed since death. Greenish color of the right iliac region is presented 2-3 days since death. Presence of the green coloration over the entire abdomen, genitals, extremities and face indicates 4-5 days after death. Full discoloration of the body suggests 1-2 weeks post-mortem interval. In 1-3 months, fulldecomposition of the body occurs. Adipocere formation and mummification take place in 3-10 months.
Contents of the Stomach and bowels. Milk, tea, coffee leave stomach fairly rapidly (15-20 min.) mixed diets (meat, vegetables) exit the stomach in 4-5 hours. Conditions like fear, shock or coma delay the emptying rate and power of digestion.
Supervital reactions. The dead tissue of the human body are proved to react to the actions of some mechanical and chemical stimuli. All those reactions can be detected during a limited time period. That is why they can be used for calculating the post-mortem interval.
Mechanical stimulation. An impact of a neurological hammer in the point of the radial bone, 4-5 sm. below the elbow joint, causes extension of hand; and takes place in the body within 1-1.5 hours since death. Impacting m. biceps brachii produces a muscular contraction and idio-muscular stiffening is formed, which can be revealed within 6-8 hours after death.
Electric stimulation. Electrical stimulation of facial muscles by the medium of a portable source of static current, results in their contraction within 6-10 hours after death.
Chemical stimulation. An action of sol. atropine 1% into the eyes of the deceased dilatates the pupil, and suggests post-mortem interval is no more than 5-6 hours.
Forensic entomological decomposition
Medicolegal entomology is a branch of forensic entomology that applies the study of insects to criminal investigations, and is commonly used in death investigations for estimating the post-mortem interval (PMI).[1][2] One method of obtaining this estimate uses the time and pattern of arthropod colonization.[3] This method will provide an estimation of the period of insect activity, which may or may not correlate exactly with the time of death.[1] While insect successional data may not provide as accurate an estimate during the early stages of decomposition as developmental data, it is applicable for later decompositional stages and can be accurate for periods up to a few years.[4]Contents
1 Decomposition
1.1 Fresh Stage
1.2 Bloat Stage
1.3 Active Decay Stage
1.4 Advanced Decay Stage
1.5 Dry Decay
2 Factors affecting decomposition
3 Current research
4 Conclusion
5 References
6 External links
Decomposition
Decomposition is a continuous process that is commonly divided into stages for convenience of discussion.[5][6] When studying decomposition from an entomological point of view and for the purpose of applying data to human death investigations, the domestic pig Sus scrofa (Linnaeus) is considered to be the preferred human analogs.[2] In entomological studies, five stages of decomposition are commonly described: (1) Fresh, (2) Bloat, (3) Active Decay, (4) Advanced or Post-Decay, and (5) Dry Remains.[2][7] While the pattern of arthropod colonization follows a reasonably predictable sequence, the limits of each stage of decomposition will not necessarily coincide with a major change in the faunal community. Therefore, the stages of decomposition are defined by the observable physical changes to the state of the carcass.[8] A pattern of insect succession results as different carrion insects are attracted to the varying biological, chemical and physical changes a carcass undergoes throughout the process of decay.[2]
A decaying carcass provides “a temporarily, rapidly changing resource which supports a large, dynamic arthropod community.” –M. Grassberger and C. Frank
Fresh Stage
Pig carcass in the fresh stage of decomposition
The fresh stage of decomposition is generally described as the period between the moment of death and when the first signs of bloat are apparent.[2][6] There are no outward signs of physical change, though internal bacteria have begun to digest organ tissues.[4] No odor is associated with the carcass.[2][6] Early post-mortem changes, used by pathologists as medical markers for early post-mortem interval estimations, have been described by Goff and include livor mortis, rigor mortis and algor mortis.
The first insects to arrive at decomposing remains are usually Calliphoridae, commonly referred to as blow flies. These flies have been reported to arrive within minutes of death or exposure, and deposit eggs within 1–3 hours. Adult flies of the families Sarcophagidae (flesh flies) and Muscidae are also common in this first stage of decomposition. First eggs are laid in or near the natural orifices of the head and anus, as well as at the site of perimortem wounds.[2] Depending on the rate of decomposition and the development time of particular blowfly species, eggs may hatch and young larvae begin to feed on tissues and liquids while the carcass is still classified in the fresh stage.[9]
Adult ants may also be seen at a carcass during the fresh stage. Ants will feed both on the carcass flesh as well as eggs and young larvae of first arriving flies.[5]
Bloat Stage
Pig carcass in the bloat stage of decompostion
The first visible sign of the Bloat Stage is a slight inflation of the abdomen and some blood bubbles at the nose.[5] Activity of anaerobic bacteria in the abdomen create gases, which accumulate and results in abdominal bloating.[2] A colour change is observed in the carcass flesh, along with the appearance of marbling. During the bloat stage the odor of putrefaction becomes noticeable.[6] Blowflies remain present in great numbers during the bloat stage, and blowflies, flesh flies and muscids continue to lay eggs. Insects of the families Piophilidae and Fanniidae arrive during the bloat stage. Ants continue to feed on the eggs and young larvae of flies.[5][6]
The first species of Coleoptera arrive during the bloat stage of decomposition, including members of the families Staphylinidae (rove beetles), Silphidae (carrion beetles) and Cleridae. These beetles are observed feeding on fly eggs and larvae.[2][6] Beetle species from the families Histeridae may also be collected during this stage, and are often hidden beneath remains.[5][6]
Active Decay Stage
Pig carcass in the active decay stage of decompostion
The beginning of active decay stage is marked by the deflation of the carcass as feeding Dipteran larvae pierce the skin and internal gases are released. During this stage the carcass has a characteristic wet appearance due to the liquefaction of tissues. Flesh from the head and around the anus and umbilical cord is removed by larval feeding activity.[5] A strong odor of putrefaction is associated with the carcass.[2]
Feeding larvae of Calliphoridae flies are the dominant insect group at carcasses during the active decay stage.[2] At the beginning of the stage larvae are concentrated iatural orifices, which offer the least resistance to feeding. Towards later stages, when flesh has been removed from the head and orifices, larvae become more concentrated in the thoracic and abdominal cavities.[5]
Adult calliphorids and muscids decreased iumbers during this stage, and were not observed to be mating.[5] However, non-Calliphoridae Dipterans are collected from carcasses.[2] The first members of Sepsidae arrive at the carcass during the active decay stage. Members of Coleoptera become the dominant adult insects at the site of remains. In particular, the numbers of staphylinids and histerids increase.[5]
Advanced Decay Stage
Pig carcass in the dry/remains stage of decomposition
Blowfly and fly larvae on 5-day old corpse of South African Porcupine (Hystrix africaeaustralis)
Most of the flesh is removed from the carcass during the advanced decay stage, though some flesh may remain in the abdominal cavity. Strong odors of decomposition begin to fade.[2][5]
This stage marks the first mass migration of third instar calliphorid larvae from the carcass Piophilidae larvae may also be collected at this stage.[2][6] Few adult calliphoridae are attracted to carcasses in advanced decay. Adult Dermestidae (skin beetles) arrive at the carcass;[6] adult dermestid beetles may be common, whereas larval stages are not[2]
Dry Decay
The final stage of decomposition is dry remains. Payne described a total of six stages of decay, the last two being separate dry and remains. As these stages are nearly impossible to distinguish between, many entomological studies combine the two into a single final stage. Very little remains of the carcass in this stage, mainly bones, cartilage and small bits of dried skin. There is little to no odor associated with remains.[2][6] Any odor present may range from that of dried skin to wet fur.[5] The greatest number of species are reported to occur in the late decay and dry stages.[2][5] The dry decay stage is characterized by the movement from previously dominant carrion fauna to new species.[5] Very few adult callihorids are attracted to the carcasss at this stage,[6] and adult piophilids emerge.[2] The dermestid beetles, common in advanced decay, leave the carcass. Non-carrion insects that commonly arrive at remains in dry decay are centipedes, millipedes, isopods, snails and cockroaches.[5]
Factors affecting decomposition
Main article: Environmental effects on forensic entomology
Understanding how a corpse decomposes and the factors that may alter the rate of decay is extremely important for evidence in death investigations. Campobasso, Vella, and Introna consider the factors that may inhibit or favor the colonization of insects to be vitally important when determining the time of insect colonization.[10]
Temperature and climate
Low temperatures generally slow down the activity of blow-flies and their colonization of a body. Higher temperatures in the summer favor large maggot masses on the carrion. Dry and windy environments can dehydrate a corpse, leading to mummification. Dryness causes cessation in bacterial growth since there are no nutrients present to feed on.
Access
Access to the body can limit which insects can get to the body in order to feed and lay eggs. In the
Reduction and cause of death
Scavengers and carnivores such as wolves, dogs, cats, beetles, and other insects feeding on the remains of a carcass can make determining the time of insect colonization much harder. This is because the decomposition process has been interrupted by factors that may speed up decomposition. Corpses with open wounds, whether pre or post mortem, tend to decompose faster due to easier insect access. The cause of death likewise can leave openings in the body that allow insects and bacteria access to the inside body cavities in earlier stages of decay. Flies oviposit eggs inside natural openings and wounds that may become exaggerated when the eggs hatch and the larvae begin feeding.
Clothing and pesticides
Wraps, garments, and clothing have shown to effect the rate of decomposition because the corpse is covered by some type of barrier. Wraps, such as tight fighting tarps can advance the stages of decay during warm weather when the body is outside. However, loose fitting coverings that are open on the ends may aid colonization of certain insect species and keep the insects protected from the outside environment. This boost in colonization can lead to faster decomposition. Clothing also provides a protective barrier between the body and insects that can delay stages of decomposition. For instance, if a corpse is wearing a heavy jacket, this can slow down decomposition in that particular area and insects will colonize elsewhere. Bodies that are covered in pesticides or in an area surrounded in pesticides may be slow to have insect colonization. The absence of insects feeding on the body would slow down the rate of decomposition.
Percent body fat of corpse
More fat on the body allows for faster decomposition. This is due to the composition of fat, which is high in water content. Larger corpses with higher percent body fat also tend to retain heat much longer than corpses with less body fat. Higher temperatures favor the reproduction of bacteria inside high nutrient areas of the liver and other organs.
Drugs
On occasion, drugs that are present in the body at death can also affect how fast insects break down the corpse. Development of these insects can be sped up by cocaine and slowed down by drugs containing arsenic.[10][11]
Current research
New research in the related field entomotoxicology is currently studying the effects of drugs on the development of insects who have fed on the decomposing tissue of a drug user. The effects of drugs and toxins on insect development are proving to be an important factor when determining the insect colonization time. It has been shown that cocaine use can accelerate the development of maggots. In one case, Lucilia sericata larvae that fed in the nasal cavity of a cocaine abuser, grew over
Medicolegal importance
Understanding the stages of decomposition, the colonization of insects, and factors that may affect decomposition and colonization are key in determining forensically important information about the body. Different insects colonize the body throughout the stage of decomposition.[2] In entomological studies these stages are commonly described as fresh, bloat, active decay, advanced decay and dry decay.[2][5] Studies have shown that each stage is characterized by particular insect species, the succession of which is depends on chemical and physical properties of remains, rate of decomposition and environmental factors.[5] Insects associated with decomposing remains may be useful in determining post-mortem interval, manner of death, and the association of suspects.[1] Insect species and their times of colonization will vary according to the geographic region,[2] and therefore may help determine if remains have been moved.[1]
Forensic entomology
Forensic entomology is the application and study of insect and other arthropod biology to criminal matters. It also involves the application of the study of arthropods, including insects, arachnids, centipedes, millipedes, and crustaceans to criminal or legal cases. It is primarily associated with death investigations; however, it may also be used to detect drugs and poisons, determine the location of an incident, and find the presence and time of the infliction of wounds. Forensic entomology can be divided into three subfields: urban, stored-product and medico-legal/medico-criminal entomology.Contents
1 History
1.1 Song Ci
1.2 Francesco Redi
1.3 Bergeret d’Arbois
1.4 Hermann Reinhard
1.5 Jean Pierre Mégnin
2 Forensic entomology subfields
2.1 Urban forensic entomology
2.2 Stored-product forensic entomology
2.3 Medico-legal forensic entomology
3 Insect types
3.1 Flies
3.2 Beetles
3.3 Mites
3.4 Moths
3.5 Wasps, ants, and bees
4 Factors
4.1 Moisture levels
4.2 Bodies of water
4.3 Sun exposure
4.4 Air exposure
4.5 Geography
4.6 Weather
5 Modern techniques
5.1 Scanning electron microscopy
5.2 Potassium permanganate staining
5.3 Mitochondrial DNA
5.4 Mock crime scenes
5.5 Gene expression studies
6 Insect activity case study
6.1 Open field habitat
6.2 Coastal sand-dune habitat
6.3 Native bush habitat
8 See also
9 Notes
10 Further reading
11 External links
History
Historically, there have been several accounts of applications for, and experimentation with, forensic entomology. The concept of forensic entomology dates back to at least the 14th century. However, only in the last 30 years has forensic entomology been systematically explored as a feasible source for evidence in criminal investigations. Through their own experiments and interest in arthropods and death, Song Ci, Francesco Redi, Bergeret d’Arbois, Jean Pierre Mégnin and the German doctor Hermann Reinhard have helped to lay the foundations for today’s modern forensic entomology.
Song Ci
Further information: Song Ci
Song Ci (also known as Sung Tz’u) was a Judicial Intendant who lived in
Francesco Redi
Further information: Francesco Redi
In 1668, Italian physician Francesco Redi disproved the theory of spontaneous generation. The accepted theory of Redi’s day claimed that maggots developed spontaneously from rotting meat. In an experiment, he used samples of rotting meat that were either fully exposed to the air, partially exposed to the air, or not exposed to air at all. Redi showed that both fully and partially exposed rotting meat developed fly maggots, whereas rotting meat that was not exposed to air did not develop maggots. This discovery completely changed the way people viewed the decomposition of organisms and prompted further investigations into insect life cycles and into entomology in general.[3]
Bergeret d’Arbois
Dr Louis François Etienne Bergeret (1814–1893) was a French hospital physician, and was the first to apply forensic entomology to a case. In a case report published in 1855 he stated a general life cycle for insects and made many assumptions about their mating habits. Nevertheless these assumptions led him to the first application of forensic entomology in an estimation of post-mortem interval (PMI). His report used forensic entomology as tool to prove his hypothesis on how and when the person had died.[4]
Hermann Reinhard
The first systematic study in forensic entomology was conducted in 1881 by Hermann Reinhard, a German medical doctor who played a vital role in the history of forensic entomology. He exhumed many bodies and demonstrated that the development of many different types of insect species could be tied to buried bodies. Reinhard conducted his first study in
Jean Pierre Mégnin
Further information: Jean Pierre Mégnin
Jean Pierre Mégnin (1828–1905), an army veterinarian, published many articles and books on various subjects including the books Faune des Tombeaux and
In this book[clarificatioeeded] he asserted that exposed corpses were subject to eight successional waves, whereas buried corpses were only subject to two waves. Mégnin made many great discoveries that helped shed new light on many of the general characteristics of decaying flora and fauna. Mégnin’s work and study of the larval and adult forms of insect families found in cadavers sparked the interest of future entomologists and encouraged more research in the link between arthropods and the deceased, and thereby helped to establish the scientific discipline of forensic entomology.
Forensic entomology subfields
Urban forensic entomology
Urban forensic entomology typically concerns pests infestations in buildings gardens or that may be the basis of litigation between private parties and service providers such as landlords or exterminators.[6] Urban forensic entomology studies may also indicate the appropriateness of certain pesticide treatments and may also be used in stored products cases where it can help to determine chain of custody, when all points of possible infestation are examined in order to determine who is at fault.[7]
Stored-product forensic entomology
Further information: Home stored product entomology
Stored-product forensic entomology is often used in litigation over insect infestation or contamination of commercially distributed foods.[6]
Medico-legal forensic entomology
Medicolegal forensic entomology covers evidence gathered through arthropod studies at the scenes of murder, suicide, rape, physical abuse and contraband trafficking.[6] In murder investigations it deals with which insects eggs appear, their location on the body and in what order they appear. This can be helpful in determining a post mortem interval (PMI) and location of a death in question. Since many insects exhibit a degree of endemism (occurring only in certain places), or have a well-defined phenology (active only at a certain season, or time of day), their presence in association with other evidence can demonstrate potential links to times and locations where other events may have occurred.[8] Another area covered by medicolegal forensic entomology is the relatively new field of entomotoxicology. This particular branch involves the utilization of entomological specimens found at a scene in order to test for different drugs that may have possibly played a role in the death of the victim.
Insect types
Further information: Decomposition, Forensic entomological decomposition, and Insect development during morgue storage and autopsy procedures
There are many different types of insect studied in forensic entomology. The insects listed below are mostly necrophagous (corpse-eating) and are particularly relevant to medicolegal entomological investigations. This is not a full list, as there are many variations due to climate.
The order in which insects feed on a corpse is known as faunal succession.
Flies
Flies (order diptera) are often first on the scene. They prefer a moist corpse for their offspring (maggots) to feed on. The most significant types of fly include:
Blow flies – Family Calliphoridae- Flies in this family are often metallic in appearance and between ten to
Flesh fly on decomposing flesh
Flesh flies – Family Sarcophagidae- Most flesh flies breed in carrion, dung, or decaying material, but a few species lay their eggs in the open wounds of mammals; hence their commoame. Characteristics of the flesh-fly is its 3-segmented antennae. They are medium-sized flies with black and gray longitudinal stripes on the thorax and checkering on the abdomen. Flesh-flies, being viviparous, frequently give birth to live young on corpses of human and other animals, at any stage of decomposition, from newly dead through to bloated or decaying (though the latter is more common).
House fly – Family Muscidae- is the most common of all flies found in homes, and indeed one of the most widely distributed insects; it is often considered a pest that can carry serious diseases. The adults are 6–9 mm long. Their thorax is gray, with four longitudinal dark lines on the back. The underside of their abdomen is yellow, and their whole body is covered with hair. Each female fly can lay up to 500 eggs in several batches of about 75 to 150 eggs. Genus Hydrotaea are of particular forensic importance.
Cheese flies – Family Piophilidae – Most are scavengers in animal products and fungi. The best-known member of the family is Piophila casei. It is a small fly, about four mm (1/6 inch) long, found worldwide. This fly’s larva infests cured meats, smoked fish, cheeses, and decaying animals and is sometimes called the cheese skipper for its leaping ability. Forensic entomology uses the presence of Piophila casei larvae to help estimate the date of death for human remains. They do not take up residence in a corpse until three to six months after death. The adult fly’s body is black, blue-black, or bronze, with some yellow on the head, antennae, and legs. The wings are faintly iridescent and lie flat upon the fly’s abdomen when at rest. At four mm (1/6 inch) long, the fly is one-third to one-half as long as the common housefly.
Coffin flies – Phoridae
Lesser corpse flies – Sphaeroceridae
Lesser house flies – Fanniidae
Black scavenger flies – Sepsidae
Sun flies – Heleomyzidae
Black soldier fly – Stratiomyidae – have potential for use in forensic entomology. The larvae are common scavengers in compost heaps, are found in association with carrion, can be destructive pests in honey bee hives, and are used in manure management (for both house fly control and reduction in manure volume). The larvae range in size from 1/8 to 3/4 of an inch (3 to
Phoridae – Humpbacked flies
• Larvae feed on decaying bodies • Some species can burrow to a depth of
Beetles
Beetles (Order Coleoptera) are generally found on the corpse when it is more decomposed.[9] In drier conditions, the beetles can be replaced by moth flies (Psychodidae).
Rove beetles – family Staphylinidae – are elongate beetles with small elytra (wing covers) and large jaws. Like other beetles inhabiting carrion, they have fast larval development with only three larval stages. Creophilus species are common predators of carrion, and since they are large, are a very visible component of the fauna of corpses. Some adult Staphylinidae are early visitors to a corpse, feeding on larvae of all species of fly, including the later predatory fly larvae. They lay their eggs in the corpse, and the emerging larvae are also predators. Some species have a long development time in the egg, and are common only during the later stages of decomposition. Staphylinids can also tear open the pupal cases of flies, to sustain themselves at a corpse for long periods.
Hister beetles – family Histeridae. Adult histerids are usually shiny beetles (black or metallic-green) which have an introverted head. The carrion-feeding species only become active at night when they enter the maggot-infested part of the corpse to capture and devour their maggot prey. During daylight they hide under the corpse unless it is sufficiently decayed to enable them to hide inside it. They have fast larval development with only two larval stages. Among the first beetles to arrive at a corpse are Histeridae of the genus Saprinus. Saprinus adults feed on both the larvae and pupae of blowflies, although some have a preference for fresh pupae. The adults lay their eggs in the corpse, inhabiting it in the later stages of decay.
Carrion beetles – family Silphidae- Adult Silphidae have an average size of about
Ham beetles – family Cleridae
Carcass beetles – family Trogidae
Skin/hide beetles – family Dermestidae. Hide beetles are important in the final stages of decomposition of a carcass. The adults and larvae feed on the dried skin, tendons and bone left by fly larvae. Hide beetles are the only beetle with the enzymes necessary for breaking down keratin, a protein component of hair.
Scarab beetles – family Scarabaeidae- Scarab beetles may be any one of around 30,000 beetle species worldwide that are compact, heavy-bodied and oval in shape. The flattened plates, which each antenna terminates, are fitted together to form a club. The outer edges of the front legs may also be toothed or scalloped. Scarab beetles range from 0.2 to
Sap beetles – family Nitidulidae
Mites
Many mites (class Acari) feed on corpses with Macrocheles mites common in the early stages of decomposition, while Tyroglyphidae and Oribatidae mites such as Rostrozetes feed on dry skin in the later stages of decomposition.
Nicrophorus beetles often carry on their bodies the mite Poecilochirus which feed on fly eggs. If they arrive at the corpse before any fly eggs hatch into maggots, the first eggs are eaten and maggot development is delayed. This may lead to incorrect PMI estimates. Nicrophorus beetles find the ammonia excretions of blowfly maggots toxic, and the Poecilochirus mites, by keeping the maggot population low, allow Nicrophorus to occupy the corpse.
Moths
Moths (Order Lepidoptera) specifically clothes-moths – Family Tineidae – are closely related to butterflies. Most species of moth are nocturnal, but there are crepuscular and diurnal species. Moths feed on mammalian hair during their larval stages and may forage on any hair that remains on a body. They are amongst the final animals contributing to the decomposition of a corpse.
Wasps, ants, and bees
Wasps, ants, and bees (Order Hymenoptera) are not necessarily necrophagous. While some feed on the body, some are also predatory, and eat the insects feeding on the body. Bees and wasps have been seen feeding on the body during the early stages. This may cause problems for murder cases in which larval flies are used to estimate the post mortem interval since eggs and larvae on the body may have been consumed prior to the arrival on scene of investigators.
Wasps – (particularly family Vespidae). Wasps exhibit a range of social difficulty, from private living to eusocial colonies. The non-breeding creature cares for the young or defend and supply for the group. Wasps are commentable for studies of evolutionary origin and maintenance of social behavior in animals.[12]
Ants – Family Formicidae. Among the most widespread and damaging of introduced species are ants. Many ants share some characteristics that ease their preamble, institution, and subsequent range expansion. One feature of their importance is the ability to establish numerically large, ecologically dominant colonies.[13]
Bees – Superfamily Apoidea.
Forensic entomologists have used bees in several cases where parents have used bees to sting their children as a form of discipline. Also, entomologists have been called upon to determine whether or not bees or wasps have been the cause of an accident. Whether through their presence or by stinging it has be speculated that these insects have been the cause of numerous automobile accidents.
Factors
Moisture levels
Rain and humidity levels in the area where the body is found can affect the time for insect development. In most species, large amounts of rain will indirectly cause slower development due to drop in temperature. Light rain or a very humid environment, by acting as an insulator, will permit a greater core temperature within the maggot mass, resulting in faster development.[14]
Bodies of water
M. Lee Goff, a noted and well respected forensic entomologist, was assigned to a case involving the discovery of a decomposing body found on a boat half a mile from shore. Upon collection of the maggot mass, only one insect, Chrysomya megacephala, was discovered. He concluded that the water barrier accounted for the scarcity of other flies. He also noted that flies will not attempt to trek across large bodies of water unless there is a substantially influential attractant.
In addition, the amount of time a maggot mass has been exposed to salt water can affect its development. From the cases Goff observed he found that if subjected for more than 30 minutes, there was a 24 hour developmental delay. Unfortunately, not many more studies have been conducted and thus a specific amount of delay time is difficult to estimate.[15]
Sun exposure
“Because insects are cold-blooded animals, their rate of development is more or less dependent on ambient temperature.” [16] Bodies exposed to large amounts of sunlight will heat up, giving the insects a warmer area to develop, reducing their development time. An experiment conducted by Bernard Greenberg and John Charles Kunich with the use of rabbit carcasses to study accumulation of degree days found that with temperature ranging in the mid 70s to high 80s the amount of deveopmental time for maggots was significantly reduced.[17]
In contrast, bodies found in shaded areas will be cooler, and insects will require longer growth periods. In addition, if temperatures reach extreme levels of cold, insects instinctively know to prolong their development time in order to hatch into a more accepting and viable climate in order to increase the chance of survival and reproduction.
Air exposure
Hanged bodies can be expected to show their own quantity and variety of flies. Also, the amount of time flies will stay on a hanged body will vary in comparison to one found on the ground. A hanged body is more exposed to air and thus will dry out faster leaving less food source for the maggots.
As the body begins to decompose, a compilation of fluids will leak to the ground. In this area most of the expected fauna can be found. Also, it is more likely that rove beetles and other non-flying insects will be found here instead of directly on the body. Fly maggots, initially deposited on the body, may also be found below.[15]
Geography
According to Jean Pierre Mégnin’s book
Calliphoridae is arguably the most important family concerning forensic entomology given that they are the first to arrive on the corpse. The family’s habitat ranges into the southern portion of the
Flesh flies fall under the family Sacrophagidae and generally arrive to a corpse following Calliphoridae. However, as previously mentioned they are capable of flying in the rain. This key advantage enables them to occasionally reach a body before Calliphoridae overall effecting the maggot mass that will be discovered. Flesh flies are globally distributed including habitats in the
Beetles are representative of the order Coleoptera which accounts for the largest of the insect orders. Beetles are very adaptive and can be found in almost all environments with the exception of
Weather
Various weather conditions in a given amount of time cause certain pests to invade human households. This is because the insects are in search of food, water, and shelter. Damp weather causes reproduction and growth enhancement in many insect types, especially when coupled with warm temperatures. Most pests concerned at this time are ants, spiders, crickets, cockroaches, ladybugs, yellowjackets, hornets, mice, and rats. When conditions are dry, the deprivation of moisture outside drives many pests inside searching for water. While the rainy weather increases the numbers of insects, this dry weather causes pest invasions to increase. The pests most commonly known during dry conditions are scorpions, ants, pillbugs, millipedes, crickets, and spiders. Extreme drought does kill many populations of insects, but also drives surviving insects to invade more often. Cold temperatures outside will cause invasions beginning in the late summer months and early fall. Box elder bugs, cluster flies, ladybugs, and silverfish are noticed some of the most common insects to seek the warm indoors.[20]
Modern techniques
Many new techniques have been developed and are used in order to more accurately gather evidence, or reevaluate at old information. The use of these newly developed techniques and evaluations have become relevant in litigation and appeals. Forensic entomology not only uses arthropod biology, but it pulls from other sciences, introducing fields like chemistry and genetics, exploiting their inherent synergy through the use of DNA in forensic entomology.
Scanning electron microscopy
Fly larvae and fly eggs are used to aid in the determination of a PMI. In order for the data to be useful the larvae and eggs must be identified down to a species level to get an accurate estimate for the PMI. There are many techniques currently being developed to differentiate between the various species of forensically important insects. A study in 2007 demonstrates a technique that can use scanning electron microscopy (SEM) to identify key morphological features of eggs and maggots.[21] Some of the morphological differences that can help identify the different species are the presence/absence of anastomosis, the presence/absence of holes, and the shape and length of the median area.
The SEM method provides an array of morphological features for use in identifying fly eggs; however, this method does have some disadvantages. The main disadvantage is that it requires expensive equipment and can take time to identify the species from which the egg originated, so it may not be useful in a field study or to quickly identify a particular egg.[22] The SEM method is effective provided there is ample time and the proper equipment and the particular fly eggs are plentiful. The ability to use these morphological differences gives forensic entomologists a powerful tool that can help with estimating a post mortem interval, along with other relevant information, such as whether the body has been disturbed post mortem.
Potassium permanganate staining
When scanning electron microscopy is not available, a faster, lower cost technique is potassium permanganate staining. The collected eggs are rinsed with a normal saline solution and placed in a glass petri dish. The eggs are soaked in a 1% potassium permanganate solution for one minute and then dehydrated and mounted onto a slide for observation.[22] These slides can be used with any light microscope with a calibrated eyepiece to compare various morphological features. The most important and useful features for identifying eggs are the size, length, and width of the plastron, as well as the morphology of the plastron in the area around the micropyle.[22] The various measurements and observations when compared to standards for forensically important species are used to determine the species of the egg.
Mitochondrial DNA
In
Mock crime scenes
A valuable tool that is becoming very common in the training of forensic entomologists is the use of mock crime scenes using pig carcasses. The pig carcass represents a human body and can be used to illustrate various environmental effects on both arthropod succession and the estimate of the post mortem interval.[24]
Gene expression studies
Although physical characteristics and sizes at various instars have been used to estimate fly age, a more recent study has been conducted to determine the age of an egg based on the expression of particular genes. This is particularly useful in determining developmental stages that are not evidenced by change in size; such as the egg or pupa and where only a general time interval can be estimated based on the duration of the particular developmental stage. This is done by breaking the stages down into smaller units separated by predictable changed in gene expression.[25] Three genes were measured in an experiment with Drosophila melanogaster: bicoid (bcd), slalom (sll), and chitin synthase (cs). These three genes were used because they are likely to be in varied levels during different times of the egg development process. These genes all share a linear relationship in regards to age of the egg; that is, the older the egg is the more of the particular gene is expressed.[25] However, all of the genes are expressed in varying amounts. Different genes on different loci would need to be selected for another fly species. The genes expressions are mapped in a control sample to formulate a developmental chart of the gene expression at certain time intervals. This chart can then be compared to the measured values of gene expression to accurately predict the age of an egg to within two hours with a high confidence level.[25] Even though this technique can be used to estimate the age of an egg, the feasibility and legal acceptance of this must be considered for it to be a widely utilized forensic technique.[25] One benefit of this would be that it is like other DNA-based techniques so most labs would be equipped to conduct similar experiments without requiring new capital investment. This style of age determination is in the process of being used to more accurately find the age of the instars and pupa; however, it is much more complicated, as there are more genes being expressed during these stages.[25] The hope is that with this and other similar techniques a more accurate PMI can be obtained.
Insect activity case study
A preliminary investigation of insect colonization and succession on remains in
Open field habitat
This environment had a daily average maximum temperature of
Coastal sand-dune habitat
This environment had an average daily maximum temperature of
Native bush habitat
This environment had recorded daily average maximum and minimum temperatures were
In literature
Throughout its history the study of forensic entomology has not remained an esoteric science reserved only for entomologists and forensic scientists. Early twentieth-century popular scientific literature began to pique a broader interest in entomology. The very popular ten-volume book series, Alfred Brehem’s Thierleben (Life of Animals, 1876–1879) expounded on many zoological topics, including arthropods. The accessible writing style of French entomologist Jean-Henri Fabre was also instrumental in the popularization of entomology. His collection of writings Souvenirs Entomologique, written during the last half of the 19th century, is especially useful because of the meticulous attention to detail to the observed insects’ behaviors and life cycles.[27] [28]
The real impetus behind the modern cultural fascination with solving crime using entomological evidence can be traced back to the works Faune de Tombeaux (Fauna of the Tomb, 1887) and Les Faunes des Cadavres (Fauna of the Cadaver, 1894) by French veterinarian and entomologist Jean Pierre Mégnin. These works made the concept of the process of insect ecological succession on a corpse understandable and interesting to an ordinary reader in a way that no other previous scientific work had done. It was after the publication of Mégnin’s work that the studies of forensic science and entomology became an established part of Western popular culture, which in turn inspired other scientists to continue and expand upon his research.[29]
DATA, THAT HELP TO DeterminE THE Time OF Death
EARLY STAGES OF DECOMPOSITION:
RIGOR MORTIS:
Muscular relaxation immediately after death is followed by the gradual onset of rigidity without shortening of the muscle. This is caused by the conversion of glycogen into lactic acid. The conversion of glycogen into lactic acid is attributed to metabolization of muscle for a short time after somatic death, or from products built up during the death event. As the pH decreases, there is aphysical change in the muscle protoplasm. There is a cross-linking of actin and myosin by the presence of excess lactic acid.
Perception of rigor is more rapid in the smaller muscles, however, all muscles are affected at a similar rate. The rigor is more evident in the short, smaller muscles earlier than in the longer, larger muscles.
Because this is a chemical process, heat accelerates and cold decelerated the process. Acidosis, uremia or other medical conditions promoting a lowered pH accelerate the process. Rigor is typically quantitated by “mild”, “early”, “moderate”, “and “complete” as a descriptive statement of degree of change. This is totally subjective and two observers may have different interpretations. Usually, perceived stiffness in motion of a joint is “mild”, difficulty requiring force to move a joint is “moderate”, and having to use great force is “complete” rigor.
Once the physical change of the muscle is forced, that degree of change will not reoccur, so that if someone has broken the rigor, it will not reform to completion. If only partial rigor is present, some rigor will continue to form.
Some conditions which affect rigor mortis include: temperature illness activity before death physical conditions where the body are found
MECHANISM ONSET MANIFESTED MAXIMUM DISAPPEARS
Physical change Immediate 1 – 6 hours 6 – 24 hours 12 – 36 hours
LIVOR MORTIS:
Livor mortis is the settling of blood to the dependant parts of the body. When cardiac activity stops, the hydrostatic pressure of the liquid blood causes it to settle to the lowest points within the body (depending on body position) and distend the dependant capillary bed. The color of the dependant part will depend on skin pigmentation and any additional compounds which may be present within the blood (i.e. carbon monoxide, etc.). The areas where the blood has settled will generally be dark blue or purple in color. Livor begins at or very soon after death since it is a function of cardiac activity. However, stasis can occur to some extent in shock and some degree can be present even while the person is technically alive.
Settling Immediate 2 – 4 hours 8 – 12 hours Livor will not usually develop where there is pressure from clothing or objects. Therefore, important information regarding whether a victim was clothed for a period of time after death or if body position was changed can be gained from a careful inspection of the livor’s distribution. Generally, time can best be supported from observation of livor and comparison with the accelerating or decelerating factors affecting that particular scene.
TARDEAU’S SPOTS/PETECHIAL HEMORRHAGES:
Accumulated blood which has settled in an area may cause capillaries in a small area to rupture so that circular or rounded areas of skin hemorrhage occur. These areas may range from pinpoint in size to 4 –
ALGOR MORTIS:
Algor mortis refers to cooling of the body. Postmortem body temperature declines progressively until it reaches the ambient temperature. The metabolism of the body generates heat which is regulated to a narrow range. If the body cools at a uniform rate, then the rate of temperature decrease could be used to accurately determine the time of death. However, the body temperature is a narrow range, not a fixed temperature. Activity, illness, decomposition, infection and absorption of heat can maintain or raise body temperature after death. The body cools by radiation (transfer of heat to the surrounding air by infrared rays), convection (transfer of heat through moving air currents) and conduction (transfer of heat by direct contact with another object). Therefore, many factors may influence the rate of heat loss. Careful consideration of the scene, clothing, victim size, activity and physical factors must be considered in interpreting cooling rate. The Glaister equation is one formula used for determining the approximate time period since death based on body temperature. 98.4% – measured rectal temperature = approximate hours since death 1.5
Temperature has to be considered in light of all the scene data. For example, a deceased person who has been in a closed car all day with the sun shining on the car who is observed at night could not be expected to cool in a regular manner. In fact, an individual in this situation may well have a body temperature above “normal”. Several individuals who have studied the effects of body cooling suggest that the rate is not constant, but rather more heat is lost during the first few hours, then as the body begins to reach ambient temperature, the rate of heat loss slows.
DESCRIPTION EYES OPEN EYES CLOSED
Corneal film minutes several hours Scleral discoloration “tachy noir” minutes to several hours Corneal cloudiness 2 hours or less 12 – 24 hours Corneal opacity 3rd post-mortem day Exophthalmos (Bulging) with gas formation with gas formation Endophthalmos (Retraction) with advanced decomposition with advanced decomposition
FOOD IN STOMACH: (This information can be gained at autopsy)
SIZE OF MEAL TIME IN STOMACH (starts to empty within 10 minutes)
Light 1 _ – 2 hours
Medium 3 – 4 hours
Heavy 4 – 6 hours
Variations:
Liquid is digested faster than semi-solid food, which is digested fasted than solid food.
Emotional state may also influence the rate of stomach emptying. Psychogenic pylorspasm prevents stomach emptying for several hours. Hyper motility may cause diarrhea.
VITREOUS POTASSIUM:
The body maintains an increased concentration of potassium in the intracellular fluid. This increase is 2- to 40 times the concentration of potassium within the plasma. This high concentration requires a balance between the electrical charges inside and outside the cell membrane and is maintained in this relatively high concentration be active metabolic forces that “pump” the electrolytes selectively across the membrane. A return to equilibrium occurs after death at a steady rate because the pumping mechanism is no longer active and the cell wall becomes a semi-permeable membrane that allows the potassium to leak through the membrane to approach equilibrium. The leak is at a steady rate because of the mechanical limits of the membrane. This steady rate provides a built-in clock that allows a projection back to the time of death. An ideal sample, protected from most trauma is the vitreous fluid of the eye. Calculations are most accurate when samples are obtained within 12 hours after death.
One formula developed for estimating the time of death based on a uniform potassium leak rate of 0.14 mEq/L/hr. is: (7.14 x K+ concentration) – 39.1 = hours since death
Soon after this data was published the formula was found to be inapplicable for some locations and/or situations. It is suggested that your medical examiner determine the rate for your specific location.
Postmortem Tissue Changes:
Decomposition: Involves two major components. These components are:
Autolysis: The process by which digestive enzymes within the body cells break down carbohydrates and proteins. Autolysis usually starts in the pancreas.
Putrefaction: The major component of decomposition which is due to bacterial activity.
Characteristics of putrefaction include:
1) Gas formation and bloating
2) Green discoloration of abdomen
3) Marbling along blood vessels-a brown black discoloration in blood vessels caused
by hydrogen sulfide gas
4) Blisters and skin slippage
5) Loss of hair and nails
Mummification: Drying of the body or its parts with “leather-like” changes. Mummification is characteristically seen on the tips of the fingers and nose. It can occur in as little as 1 – 2 days.
Skeletonization: Characterized by removal of soft tissue. Occurs largely as a result of insects and animals.
Adipocere: Formation of a waxy substance due to the hydrogenation of body fat. A moist, anaerobic environment is required for the formation of adipocere.
EXTENSIVELY DECOMPOSED/SKELETONIZED REMAINS:
Should be treated as any other scene involving careful examination and documentation of the scene, collection of evidence, etc.
The best approach is to plan ahead. Another day at this stage will probably not change the scene significantly, but could make the final conclusions better.
Use the services of a forensic anthropologist if possible. The weathering of bones depends considerably on:
Buried or not buried
Climate
Moisture
Elevation
Terrain
Protection Insect/animal/human intervention Check weather bureaus for rainfall, temperatures, etc.
INSECT INFESTATION (FAUNA):
INSECT INFESTATION MINIMUM POSTMORTEM INTERVAL
Body lice Outlive host by 3 – 6 days Blow flies May deposit ova before or at death –larva (maggot) – hatch within 18 – 24 hrs. -pupae/casings + week
Insects/Arthropods In temperatures greater that 40o F. –Highly dependant of locale, temperature, season
-Collect samples in preservative (85% alcohol) and take to an entomologist -Collect soil sample from around body (within
PLANT LIFE (FLORA):
1) Grass/plants beneath an object wilt, turn yellow or brown and dies. The rate depends on type of plant, season, climate, etc.
2) Seasonal plants or remnants may help indicate a range of time.
3) Collect dead and drying grasses, twigs, flowers, etc. and take to a local botanist.
METHODS FOR THE ESTIMATION OF TIME OF DEATH…SUMMARY
Rate: Method: Estimation by evaluating the presence/absence of an indicator in a deceased in conjunction with the known behavior of such indicators.
Concurrence Method: Estimation by evaluating events which happen at or near the time of death, or offer information suggesting a time period for the death event.
METHOD TYPE INDICATOR
Rate Method Rate of drying or discoloration of blood pools
Rate Method Rigor Mortis
Rate Method Livor Mortis
Rate Method Algor Mortis
Rate Method Decomposition
Rate Method Flora (plants) around body
Rate Method Fauna (insects) around body
Concurrence Method Time of last known meal
Concurrence Method Stopping of watch (due to trauma/damage)
EVIDENCE FOR ESTIMATION OF TIME OF DEATH:
1) Corporal Evidence: In the body
2) Environmental & Associated Evidence: In the vicinity and general surroundings
3) Anamnestic Evidence: Based on the decedent’s ordinary habits and daily activities
CORPORAL EVIDENCE ENVIRONMENTAL & ASSOCIATED EVIDENCE
ANAMNESTIC EVIDENCE
Stage of decomposition of internal organs vs. exterior of body Uncollected mail/newspapers Usual activities soot in airway (fire/smoke inhalation).
Lights on or off Walking & sleeping patterns Evidence if medical conditions Alarm clock set Eating habits, times, types of food.
Alcohol/drug levels Food on stove/in refrigerator Appointments Beard/nails/hair Type of clothing day/night indoors/outdoors seasonal condition of clothing (mold/leached dyes, etc. Answered/unanswered correspondences Presence of sale slips or receipts in clothing Animals/pets in house
IDENTIFICATION OF THE DEAD
Primary Physical Characteristics (characteristics which are very difficult for a person to change during life.
Some of these characteristics will appear to alter post mortem):
• Sex – usually obvious.
• Age – external appearances, internal degenerative disease, bones, joints.
• Height or stature – N.B. height of corpse differs from that in life by up to 2-
• Weight – corpse often appears of different build to that in life
• Race
• DNA (unique to every individual. Considered in detail in the lecture notes on Genetics & Parentage Testing)
Secondary Physical Characteristics (characteristics which can change during life, either deliberately by deceased or as a result of medical/dental interference.
Some of these characteristics will appear to alter post mortem):
• Skin colour (alters post mortem)
• Eyes – more useful in caucasians than negroid & mongoloid races. Colour can alter PM
• Teeth – very resistant and bear much useful information.
• Hair – colour, style, length, beard/moustache.
• Scars – surgical procedures and prostheses.
• Tattooing – seen even if the body is putrefied.
• Fingerprints
• External peculiarities – circumcision, moles, warts.
• Deformities
• Clothing and other objects
• Jewellery
• Cosmetics
DNA is unique to every individual (except monozygous (identical) twins. DNA comparisons allow for definitive identification of an individual. The biology of DNA and the procedures for analysis are considered in detail in the lecture notes on Genetics & Parentage Testing. This is forensically useful in the living (strong evidence of involvement in assault, rape, disputed paternity) and the dead (DNA survives in bone for many years, comparison of DNA with family members)
IDENTITY OF DECOMPOSED OR SKELETAL REMAINS
Are the remains human or animal? (butchers offal, skeletal remains of dead pets etc. may be found in unlikely places) If the remains are only bones:
1. Are they really bones? (wood, stones)
2. Are they human?
3. How many bodies?
4. How long dead? – recent or ancient (e.g. construction or digging at an old burial site)
5. Cause of death?
6. Sex?
7. Age?
8. Race?
9. Stature?
Try out an exercise in identification of skeletal remains for yourself.
Sex : Straightforward in intact bodies except in transvestites, adrenogenital syndrome and hermaphrodites. In mutilated/dismembered or charred bodies the internal sex organs, especially the uterus, cervix and prostate are resilient.
SEX DETERMINATION FROM SKELETON
Based on appearance of pelvis, skull, sternum, long bones. Pelvis is the most important bone for sex determination. Subjective and objective differences are seen between male and female pelves.
Subjective sex differences in the pelvis
MALE FEMALE
Pelvis as a whole Thick, heavy, markedly
muscular
Smoother, lifgter, more
spacious
Brim Heart shaped Circular or elliptical
Body of pubis Triangular shape Quadrangular
Sub pubic arch Inverted V shaped Inverted U shaped
Greater sciatic notch Deep and narrow Broad and shallow
Sacro iliac joint Large Small
Sacrum Long and narrow Short and wide
Objective sex determination from pelvis is based on anatomical pelvic measurements.
SEX DETERMINATION FROM SKULL
Supra orbital ridges
Mastoid process
Palate
Orbit
Mandible
Inexperienced persons can correctly sex over 90% of caucasian skeletons but only 83% of skeletons of Americaegros.
RACE DETERMINATION FROM BONES
The skull is the only reliable bone. It is not possible to narrow down the identification to racial stock:
• Caucasian (all whites)
• Negro (all blacks – African, American Negroes and West Indians)
• Mongoloid (Chinese, Japanese, American Indians)
Thus skulls of British, Germans, French or Swedes cannot be distinguished from one another.
Similarly Japanese skulls are similar to Chinese skulls.
Mongoloid race has characteristically “shovel-shaped” concave upper incisor teeth.
Cheekbones (Zygomatic arches): determine facial width. More prominent in Mongoloids. Width between eyes greater in mongoloids. Nasal openings: Wider and flatter in Negroids. Narrow in Caucasians.
Femur: Tends to be straighter in Negroids.
DETERMINATION OF STATURE FROM BONES
Long bone length (femur, tibia, humerus) is proportional to height. Tables are used. Fairly reliable up to the age of epiphyseal fusion. There are sex, race, nutrition and personal variations to consider.
AGE DETERMINATION FROM SKELETON
Sex has to be taken into account as bone development and epiphyseal fusion is different between the sexes.
Epiphyseal fusion. The pattern of fusion of bone ends (epiphysis) to bone shaft (metaphysis) in each bone indicates age. Charts & tables are used. Cranial suture fusion is less reliable. Pubic symphysis changes slightly with age. Arthritic changes, osteophytes and osteoporosis give further clues.
Ossification centres. Useful only in foetuses and babies. May be determined radiologically or by cutting into ossification centres. May be confirmed histologically. Most important centre in medico-legal work is the distal centre of the femur. This is present at birth and indicates a full term baby.
THE DATING OF HUMAN SKELETAL REMAINS
Are they ancient or modern bones? (i.e. greater or less than 50 years). Rate of skeletonisation is highly variable. In the tropics a body can be reduced to a skeleton in 3 weeks. Remarkable preservation of body is seen in acidic peaty soil (e.g. “Pete Bogg” from
Naked eye appearance is unreliable:
Tags of soft tissue, periosteum, ligaments etc, indicate less than 5 years old.
Soapy texture of surface indicates age less than a few decades.
Light, crumbling bones are likely to be a century or more old.
Laboratory tests –
1. Immunological reaction between bone extract and anti human serum ceases within
months of death.
2. If blood pigments are present bones are usually less than 10 years old.
3. Up to 20 amino acids may be identified in bones less than a century old.
4. Fluorescence of freshly sawn bone surface under UV light diminishes after 100 years.
5. New bones contain 4.0 – 4.5 gms% nitrogen; 2.5 gms% indicates approximately 350
years.
6. Radioactive carbon dating indicates which century. Individualising skeletal features Bone disease (Paget’s disease, tumours) Previous injury to bone (fracture callus, prosthesis, metallic fragments). Comparison of trabecular pattern of bone. Pattern of skull’s frontal air sinuses. Outline is unique and comparisons with antemortem X-rays are useful. Facial reconstruction Skull can be scanned into a computer and “fleshed” by computer reconstruction to give likely facial appearance in life. Unfortunately eye colour, hair colour and lips are independent of bony structure.
THE MEDICO-LEGAL AUTOPSY
The purposes and administrative aspects of death investigation are dealt with in the lecture notes on Death
Investigation. Here, the practical aspects will be considered.
The aims of death investigation are to answer the following questions:
1. Who died? (identification of the deceased)
2. Where? (place of death)
3. When? (time of death)
4. Why? (cause of death)
5. How? (manner & mechanism of death)
Autopsy is only one part of death investigation. Body, History and Scene are equally important
(diagnostic triangle).
Each of the three aspects of the death investigation process are equally important (like a three legged
stool, which will fall over if one leg is removed or even shortened!)
1. Scene:
• Attendance by police officers, CID, family doctor, police surgeon, forensic pathologist, forensic
scientists.
• The aim is to collect the maximum of information with the minimum of disturbance.
• Potential for professional conflicts.
• Photography, videos, trace evidence.
2. History:
• Social – from relatives, friends, police.
• Medical – from GP, hospital notes. Often indicates the likely cause of death
• Psychiatric – from GP, hospital notes. May indicate possibility of suicide.
3. The medico-legal autopsy:
The medico-legal autopsy differs from the hospital autopsy in two major respects:
• Purpose:- What happened? to Who, When, Where, Why, and How.
• Technique:- The external examination assumes much greater importance, special dissection techniques and examinations, evidential materials, report formulation or commentary.
AUTOPSY AUTHORITY
Instruction/consent for autopsy is derived from a law officer having jurisdiction, i.e. the Coroner or Procurator Fiscal.
Authority for autopsy is permanently recorded: how received, from whom, and when:
1. Two doctor case if legal proceedings likely (homicide, road accident).
2. One doctor examination in most non-suspicious cases (accident, suicide).
3. Autopsy or external examination only (death obviously natural) at the discretion of the pathologist.
4. External examination (“View & Grant” Preferred) if Fiscal considers an autopsy is not necessary
IDENTIFICATION OF DECEDENT
The body must be identified to the Pathologist as the decedent for whom autopsy authority has been given. Identification in 2 doctor autopsies is performed in front of the 2 doctors performing the autopsy. Initial (provisional) identification may be:
• Visual (relatives),
• Circumstantial (address, car, papers, cards, keys, clothes),
• Medical (scars, teeth, x-rays, DNA).
Permanent record is made of the method of formal identification:
• personal (name, title, address),
• body tag (record all details),
• accompanying documentation.
PERSONAL EFFECTS AND CLOTHING
By contrast with the hospital autopsy, the examination of personal effects and clothing is an integral part of the medico-legal autopsy providing information on life style, events leading to death, and often the actual cause of death. List of jewellery, valuables, and personal effects.
Listed description of the clothing:- type of garment, colour, fabric type, location, if disarranged, wet/moist/dry, stains (blood, vomit, faeces, urine, semen, dirt, oil, soot, etc.), damage (holes, cuts, tears).
Clothing findings are correlated with historical and scene information, e.g. appropriateness of clothing, source of stains, trace materials. Clothing findings must also be correlated with other autopsy data, e.g. injuries, source of blood stains.
EXTERNAL EXAMINATION
This is a detailed head to toe examination of the naked body, documenting stains and soiling, general and specific individualising characteristics, post-mortem changes (temperature, lividity, rigor mortis, putrefaction).
The location, extent and type of staining or soiling of the body are described e.g. dual flow pattern of blood from a wound, high velocity impact blood spatter from gunshot wound, coffee grounds vomitus and melaena (upper gastrointestinal haemorrhage), antiseptic from medical intervention.
General body characteristics are recorded, namely:- racial group, height, weight, head hair (colour, dyed, length, style, balding), eyes (colour, pupil size, conjunctival congestion or petechial haemorrhages, jaundice, prosthesis), nose and ear canals (blood, pus), earlobes (piercing, earlobe creases), face (hirsute woman, clean shaven, beard, moustache), mouth (vomit, blood, tablet debris, teeth, dentures), breasts (normally developed, atrophic, hirsute), genitalia (pubic hair pattern, circumcised, palpable testes), feet (general hygiene, bunions, ingrowing nails).
More specific identifying characteristics are described fully: tattoos (location, design, colour, names), scars (surgical and non-surgical, needle tracks, striae), skin lesions (naevi, senile keratoses, other skin diseases), prosthesis, pacemaker.
Post-mortem changes are documented, namely:- body temperature to touch (alternatively state if the body has been refrigerated), rigor mortis (extent and degree), hypostatic lividity (distribution, dual pattern, colour, contact pallor), putrefactive changes.
INJURIES (EVIDENCE OF INJURY)
All injuries are described systematically either by grouping them according to anatomical location, e.g. right arm, anterior chest, left leg (as in multiple injuries in vehicular collisions), or iumerical order (e.g. where the number of injuries is few or where each and every injury is particularly important as in multiple stab wounds). If numbered, it is stated that the order of numbering does not imply sequence of infliction or degree of severity.
Injuries are described as to their type, e.g. bruise, abrasion, laceration, incised wound, puncture or stab wound, gunshot wound, burn, fracture. Injuries should be described with regard to their location, size, shape and colour. The location of the wound is given by general description (e.g. on the left side of the face, or over the rib cage, immediately below the left breast) and by precise location in relation to fixed anatomical landmarks (analogous to latitude and longitude). Suitable vertical landmarks are the heel, superior margin of the pubic symphysis, superior anterior iliac crest, supra-sternal notch, orbital ridge, and crown. Suitable horizontal landmarks are any midline structures, e.g. umbilicus, midline of the sternum and glabella.
The size of an injury is measured in two dimensions. The shape can be related to a geometric shape or common object, often supplemented with drawings, sketches or by tracing patterned injuries onto acetate sheets.
Internal injuries are described in continuity with the related externally apparent injuries, e.g. the bruising and abrasion to the chest, then the fractured ribs, then the lacerated lung and haemothorax. This organisation of the final report frequently does not correspond with the order of dissection and dictation of findings. In the final report remote injuries are segregated from recent injuries under separate subheadings.
SIGNS OF MEDICAL INTERVENTION
Medical intervention is described under a separate heading. This includes all medical equipment attached to, or accompanying, the body, e.g. urinary catheter, endotracheal tube, oral airway, rods for external fixation of fractures, arterial and intravenous lines, intravenous solutions or blood (with details of contents).
External surgical incisions are described in continuity with the internal evidence of surgery.
INTERNAL EXAMINATION
The internal examination is systematic description of natural disease and does not include recent injuries, all of which have been previously described under the appropriate heading. Negative observations are included, e.g. no pulmonary thrombo-emboli, no significant coronary artery atherosclerosis, no skull fracture, etc.
OTHER EXAMINATIONS
Any special dissections, e.g. neck dissection, or further examination of organs e.g. brain after formalin fixation, together with microscopic, biochemical, and toxicological studies should be described at this point.
Cause of death: the disease process or injury responsible for initiating the train of events, brief or prolonged, which produces the fatal end result. Mechanism of death: the physiological or biochemical derangement produced by the above cause, which is incompatible with life; i.e. how the disease or injury leads to death
Manner of death: the fashion in which the cause of death came into being; i.e. whether natural, accident, suicide, homicide, unclassified (alcohol/drug deaths) or undetermined
Cause Mechanism Manner
Atherosclerotic coronary artery disease
Electrical arrhythmia or heart failure
Natural
Stab wounds Internal or external blood loss Homicide, Suicide or Accident
Hanging Asphyxia Suicide
Strangulation Asphyxia Homicide
OPINION (CONCLUSION OR COMMENTARY)
This section is interpretative and subjective, representing the opinion of the author. It includes the cause of death as appearing on the death certificate. The commentary is in simple English and brings together all the relevant information obtained from examination of the body, the scene of death and the history of the decedent. Information obtained second-hand (hearsay) may be included e.g. from police reports, medical records, fire investigation reports. The relevant issues are addresses i.e. what happened, to who, when, where, why and how. It may be as brief or as detailed as the need dictates It is directed to the law officer investigating the death and any other legally interested parties who may obtain access to the report subsequently.
The commentary is analogous summary of a hospital autopsy which brings together the pathological autopsy findings with the clinical findings and subsequent progress.
SIGNATURE
All medico-legal reports require the original signature of the author. Relevant degrees and other qualifications are given. Occupational titles, e.g. Lecturer in Pathology, may be included. You can try out death investigation exercises (mostly natural deaths) at The Virtual Autopsy Website
ANAESTHETIC AND POST-OPERATIVE DEATHS
Aproximattelly in 166 patients submitted to surgery die within 6 days but only
Difficulties with such cases:
1) Autopsy may be technically difficult, due to the effects of surgery and anaesthesia being superimposed on pre-existing natural disease or trauma.
2) Naked eye changes may be minimal or absent at autopsy.
3) An understanding of the possible mechanisms of death in such cases often requires specialist knowledge outside pathologist’s normal experience.
4) Even unspoken inference of possible medical impropriety makes relationships between pathologists, anaesthetists or surgeons very sensitive.
To overcome these difficulties:
1) Autopsy is performed with minimal delay. Medical intervention should be left intact by medical & nursing staff.
2) Clinical casenotes, x-rays, laboratory results are studied prior to autopsy.
3) Polite and professional first hand discussions with anaesthetist and surgeon involved are encouraged. They should be invited to attend autopsy and to discuss the findings.
4) Specimens should be retained for further investigations, where appropriate, e.g. toxicology, biochemistry, microbiology and histology.
In considering the cause of death, the physical status of the patient prior to surgery must be considered.
The question “would death have occurred when it did if the operation had not been performed ?” is often impossible to answer.
The American Society of Anaesthesiologists have devised a classification system to grade the preoperative condition of the patient:
ASA1: those with no pre-existing serious disease and have a minor, localised condition requiring surgery, e.g. fit man with inguinal hernia.
ASA2: those with a serious disease but have no limitation of their activities (the condition may be pre-existing or the result of the condition requiring surgery), e.g. mild angina, mild hypertension, chronic bronchitis.
ASA3: those with a serious disease causing some limitation of their activities, e.g. moderate angina, previous myocardial infarction (heart attack), severe chronic bronchitis.
ASA4: those with a serious disease that limits their activities and is already a threat to life, e.g. severe angina at rest, acute myocarditis, chronic bronchitis with respiratory failure, perforated peptic ulcer.
ASA5: Moribund patient with little chance of survival, submitted to surgery as a last resort, e.g. ruptured aortic aneurysm, severe trauma, massive pulmonary embolism, severe peritonitis due to perforated colon.
Suffix (E): indicates the need for emergency surgery and indicates the patient’s condition is worse than for one undergoing planned surgery, e.g. fit man whose hernia becomes strangulated (IE).
Class 1 – 3 requires full medicological investigation.
Class 4 and 5, where death is anticipated, there is less need for full investigation.
The cause of death after surgery/anaesthetic may be:
a) The result of the disease or injury for which the anaesthetic/operation were being carried out.
Was there any delay in treatment?
Was the timing of operation appropriate?
b) The result of some other disease or abnormality.
Should this have been diagnosed prior to surgery?
Where all measures taken to reduce any known preexisting risks?
c) The result of a surgical mishap.
Accident (slipped ligature or clamp)
Unusual difficulties (adhesions due to previous surgery, anatomical variants)
Error by surgeon (? negligence)
d) The result of anaesthetic mishap.
Cardiac arrest (nerve stimulation by instrumentation)
Excess anaesthetic agent given (overdose)
Airway obstruction (position of patient, inhalation of false teeth, blood, vomit)
Faulty equipment (anaesthetic machine empty, disconnectied or blocked, electrical fault)
Malignant hyperpyrexia (a rare inherited muscle disease causing excessive fatal heat production by muscle in response to some anaesthetic agents)
NEGLIGENCE
Definition “the breach of a duty to use reasonable care as a result of which there is damage to another”.
Proof requires three elements to be established
1. Legal duty of care must be owed
2. Breach of that duty, by omission (something they did not do but should have) OR by commission (something they did but should not have). Behaviour has fallen short of the required standard and it is reasonably foreseable that such careless behaviour could damage the patient.
care required by a doctor is the standard of a reasonably skilled and experienced doctor working in
that field. Judged by peer review.
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