Changes after Death PDF

The Medicolegal Importance of Putrefaction: 1.Sure sign of death. 2.The time passed since death is approximately estimat...

The Medicolegal Importance of Putrefaction: 1.Sure sign of death. 2.The time passed since death is approximately estimated by the extent of putrefaction: a.After 2 days in winter or 1 day in summer: Greenish discoloration in the right iliac region of abdominal wall (ceacum is full of bacteria & fluid stools). Arborisation (marbling) of blood vessels on the root of the neck, over the shoulder and on the Post-mortem change in the eye, the so- called ‘tache noire’. These are brown areas groin. This occurs due to the distension of veins of scleral drying caused by failure of the by putrefactive gases and bluish to green lids to close after death. discoloration by altered blood (sulph-Hb).)]. Blisters of putrefaction should not be Estimation Of Post-Mortem Period confused with blisters of burns. A Definition: It is the time passed since putrefactive blister contains mainly gas & death till examination of the cadaver by little reddish colored fluid with no evidence the physician Medico-legal importance: of vital reaction. In civil cases: as in cases of inheritance. In criminal cases: in order to establish the involvement of a suspect in a crime of homicide  Early Changes Early Changes Rigor mortis Rigor mortis Chemical reaction – Usually complete within 12hours Decrease in ATP and Static until decomposition begins Secondary flaccidity within 24-50hours an increase in ADP + LACTIC ACID Onset smaller muscles first – jaw (1- Cadaveric spasm – 4hours), then arms and finally legs (4- Instant rigidity High level of physical or emotional stress before death 6hours) Drownings, war deaths, gunshot suicides Temperature dependent Early Changes Rigor mortis Warm and flaccid, dead less than 3hours Warm and stiff, dead 3-8hours Cold and stiff, dead 8-36hours Full rigor mortis 12 hours post-mortem. Cold and flaccid, dead more than 36hours  Post-mortem hypostasis: pink or bluish color to the lowest areas of the body and it is this colour change that is called post- mortem hypostasis or lividity. Cadaveric spasm, an instantaneous form of rigor, in the victim of a fall into water. The victim was recovered within a short time (as can be seen from the absence of skin maceration) but had grass from the river bank firmly clutched in the hand. Early Changes Early Changes Hypostasis Hypostasis Blood vessels relax Visible within 2 to 3 hours Blood settles under the influence of gravity Usually fixed after about 12hours Positional Useful as an indicator of movement of the Colour depends on colour of the blood body after death Normally RED to PURPLE - depending on the oxygen level in blood  Early Changes Hypostasis Cherry pink in carbon monoxide poisoning Pink in hypothermia Deep pink in cyanide poisoning Post-mortem hypostasis in the normal distribution. The pale areas are the Brown in methaemoglobinaemia result of pressure against a hard supporting surface. Bronze in Clostridia perfringens septicaemia - Cooling of the body after death: Newton’s Law of Cooling states that heat will pass from the warmer body to the cooler environment and the temperature of the body will fall. - Post-mortem hypostasis in a death from hanging. The discoloration of the skin is in the legs and hands, due to the vertical posture after death.  Early Changes Cooling of the body Normal temperature 37C After death – circulation and cell metabolism stop, inside and outside temperatures equilibrate, after delay of minutes to hours ‘core’ temperature begins to fall Late Changes Decomposition Putrefaction Mummification Adipocere Measuring the rectal temperature at the scene of a murder. This should be done only after forensic procedures such as rectal swabbing have been completed. Skeletonisation Normally the temperature should be taken at the mortuary where removal of clothing can be carried out with full photographic and forensic science monitoring. Animal scavenging In this case the body was unclothed at the scene and the circumstances did not warrant rectal swabbing.  This ‘greening’ is the result of the extension of the commensal gut bacteria through the bowel wall and into the skin, Decomposition/putrefaction: the warmer where they decompose haemoglobin, the temperature, the earlier the process resulting in the green colour. When starts and the faster it progresses. In present in the superficial vessels, results temperate climates, the process is usually in linear branching patterns of variable first visible to the naked eye at about 3–4 discoloration of the skin that is called days as an area of green discoloration of ‘marbling’, the prostate and the uterus are the right iliac fossa of the anterior relatively resistant to putrefaction and they abdominal wall. may survive for months, as may the tendons and ligaments, bones may remain for years. Immersion and burial: Immersion in water or burial will slow the process of Putrefaction decomposition. Casper’s Law (or Ratio) Liquefaction of tissues states that: if all other factors are equal, then, when there is free access of air, a Chemical and enzymatic process body decomposes twice as fast than if Bowel bacteria proliferate, breakdown Hb. immersed in water and eight times faster Green discoloration abdominal wall than if buried in earth. The level of Gas formation, swelling and bloating moisture in the surrounding soil and acidity ‘marbling’ of skin due to bacteria in vessels of the soil will both significantly alter the speed of decomposition.  Putrefaction Skin blistering, ‘slippage’ Liquefaction of internal organs e.g. bowel, lungs and brain Purging of fluid from orifices Vessels, uterus and prostate relatively Moderately early changes of decomposition, showing gaseous distension resistant of scrotum and abdomen, and skin slippage and blistering in dependent areas. This was after about one week since death, but the +/- insects – common flies, bluebottles changes vary greatly with environmental temperatures. etc., lay eggs which hatch into maggots Post-mortem decomposition showing putrefactive changes in the face, arms and trunk after one week in a warm room. The illustration shows the contrast sometimes Post-mortem decomposition of about 2 weeks’ duration in water in a seen between one part of the body and another, as the legs are hardly affected. The summer temperature. There is ‘marbling’ of he skin where breakdown face, neck and hands are swollen with gas, and the clothing is stained by leaking products of haemoglobin have stained the venous channels. skin blisters. The tongue is protruding because of gas pressure from the tissues below. Death was due to carbon monoxide poisoning caused by faulty installation of a room heater.  Bloating of face and effusion of blood-tinged fluid from the Almost complete destruction of the facial soft tissues by maggots. nostrils and mouth. A body recovered from water, Postmortem time about 2 weeks in a centrally heated apartment. postmortem time approximately 11 days. Adipocere formation in a body after 3 months in the sea. Subcutaneous Marine predation in a body after 3 months in the North Sea. The fat has been released from crustacean bites on the skin and has been victim was from an oil rig and had floated on the surface in a life converted into adipocere, which has been rolled by wave action within jacket. Much of the skin has been removed by crustaceans, and the clothing to form ovoid masses. the arm muscles by larger fish who have cleaned out most of the body cavity.  Forensic entomologist, who can determine a probable time of death – in the region of days to months – from examination of the populations and stages of development of the various insects that invade a body. Complete conversion of a body to adipocere. The body was recovered from a deep lake 8 years after disappearing in a boating accident during a heavy storm. Mummification Dry conditions, cool, air flow Dessication or tanning Newborns – sterile Attracts moths and beetles Mummification in a man dead in a locked room for 10 weeks. The corpse is dry and leathery, with very little moist putrefaction.  Extensive mould formation and lack of putrefactive changes in a child who accidentally locked himself in a Loss of all soft tissues of head box and asphyxiated. The body was not found and neck, in areas not covered by clothing, for 6 weeks. by post-mortem animal predation. Post-mortem rat bites of the orbit. Such injuries are – not unnaturally – often regarded with suspicion by the police. The complete absence of bleeding or reddening of the wound margins, as well as the unlikely shape and situation of the injury, make its postmortem origin obvious. A body recovered from the Baltic Sea with numerous superficial skin defects on the face and neck due to postmortem predation, probably by the crustacean Saduria entomon, shown in the inserted picture with a smaller shrimp in the middle.  Adipocere Damp or wet conditions Chemical change – hydrolysis Body fats changed into waxy material – saponification Retains shape and outline of the body or A post-mortem animal bite that was mistaken for a criminal assault. The old lady was found locked in with a cat, having died from a gastric some body parts haemorrhage. The wound has not bled, the margins are not reddened and tooth crenations can be seen round its edge. Skeletalisation Loss of soft tissues - Skeletalization: in a formally buried body, Climate dependent the soft tissues will be absent by 2 years. Assisted by animal activity Examination of the bone marrow space may reveal residual organic material that Remains scattered can sometimes be suitable for specialist Anthropologist required for identification DNA analysis. Only bone injury apparent in homicide cases  Post-mortem injuries: It is not true to say that post-mortem injuries do not bleed because many do leak blood. In general, post-mortem injuries do not have a rim of an early inflammatory response in the wound edges. References Forensic pathology of B. knight Simpson’s Forensic Medicine 0