Thanatology The scientific study of death.

Death Death means persistence stoppage of all vital processes in the body. OR Permanent cessation of both circulation and respiration. OR Irreversible loss of brain function (brain stem).

Different tissues and organs in a living body die at different rates 1-Somatic death: 2- Cellular (molecular) death:

Importance of determination of clinical death 1.To write death certificate. 2.To stop life support measures. 3.To determine the moment of death (e.g. inheritance). 4.For organ transplantation considering the concept of brain stem death. 5.For rapid burial in cases of epidemics e.g. cholera.

The immediate signs of death: 1-Pallor and loss elasticity of the skin. 2-Ocular signs includes. 3-Primary flaccidity of the muscles. 4-Cessation of circulation: 5- Cessation of respiration:

Eye signs Postmortem (PM)

Post mortem changes which appear during the first 12 hours after death 1- Cooling of the body: The body after death is estimated to loss about 1.5 C every hour in the first 6 hours after death {i.e. 9 C}. On the second 6 hours the body looses 1 o C every6hours.

2-Post-mortem hypostasis (PM lividity or PM suggilation): Blood tends to accumulate in the capillaries and small veins in the dependent parts of the body. Hypostasis occurs in the skin and also in viscera.

Post-mortem hypostasis (PM lividity or PM suggilation): Starts Appear Complete Ante mortem It is present in all bodies, although it may be unremarkable in some cases (e.g. dark skin). It is present in all bodies, although it may be unremarkable in some cases (e.g. dark skin).

ML importance of hypostasis: It is a sure sign of death. Estimation the time pass science death. Position of the body at the time of death The cause of death. Mistaken with bruises (Contusions).

3- Rigor mortis : The initial flaccidity of the body after death is soon followed by stiffening or rigor mortis.

Mechanism Rigor mortis is due to the disappearance of adenosine triphosphate (ATP) from the muscle. Leading to muscle stiffness

Appearance Rigor mortis is reported first to appear in the eyelids, face, lower jaw and neck. Then, it involves the trunk and limbs. Complete in 12 hours

Medico legal importance of rigor mortis Medico legal importance of rigor mortis: 1-It is sure sign of death. 2-Estimation the time pass since death 3-It fixes the body's position at the time of death. 4-It may suggested to the cause of death, 5-It may be mistaken with other conditions of stiffness after death as:

a) Cadaveric spasm : Onset Mechanism Type of death Type of muscle Extension Primary flaccidity

b) Heat stiffness This stiffness due to coagulation of the muscles proteins in cases of burning leading to stiffening of the body and rigor mortis does not develop in the muscles

c) Cold stiffness: This cases are due to frozen of the body, resulting in freezing of inter and intra cellular fluids of the tissues and also freezing the synovial fluids in the joints.

Cadaveric spasm in 43-year-old male with razor in right hand.

4-Putrefaction : It is the last stage that takes place in the dead body. After 24 Hs in summer of 36 Hs in winter, Marbling phenomenon (48H) After 1-3 days after death, the green discoloration is all over, the face.

4-Putrefaction : One Week after death putrefactive bulla Two weeks after death there is peeling of the skin At 6 months after death At one year after death

Factors affecting the rate of putrefaction: 1. Age. 2. Causes of death. 3. Temperature. 4. Moisture. 5. Air current. 6. Manner of burial. 7. Blood content.

Conditions that may replace putrefaction: 1- Adipocere formation Definition. Mechanism. Condition required. ML importance.

Adipocere

Buried a few years prior to this exhumation

A woman drowned and was submerged for seven months.

2- Mummification:

The natural mummification

Mummification brown skin

3- Embalming:

Embalming neck veins

4- Maceration Intrauterine fetal death

Estimation of post-mortem interval: Entomology of the dead From gastric content. Hypostasis RM Putrefaction Adipocere Mummification

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