10. Thanatology dental forensic dept.pptx

thanatology

1. T h a n a t o l o g y Department of Forensic Odontology Faculty of Dental Medicine, Universitas Airlangga @forensicodontounair

2. Introduction Thanatology is the scientific study of death and post-mortem changes The importance of learning thanatology: Estimates the time of death Differ the post-mortem changing after someone death Determine if someone death or not

3. Death Respiratory system Blood circulation Completely and Permanently

4. DEATH SOMATIC DEATH (Clinical/ systemic death) CELLULAR DEATH (Molecular death) Respiratory & blood circulation stopped Cellular function stopped

5. Somatic death Respiratory and blood circulation stopped  anoxia  cellular aerobic process stopped, but anaerobic process is still remaining Some organ/ tissue will remain “life” even the respiratory & blood circulation was stopped, such as: - Nervous system  + 5 minutes after somatic death - Muscular  + 3 hours after death - Eyes  within 4 hours

6. Cellular death Sign of the cellular death: Algor mortis Livor mortis Rigor mortis Early post-mortem changes (skin, eyes, etc) Decomposition process

7. Livor Mortis / post-mortem lividity Settling of blood, based on gravity, becomes evident in the skin of the dependent parts of the body Typically has a dark red -purple color within a couple of hours after death More difficult to recognize in dark skin Areas of skin exposed to pressure, do not develop lividity

8. Livor Mortis / post-mortem lividity Early on, livor mortis is easily blanchable, or unfixed (if pressure is applied to it, the blood is forced out of the skin, leaving an area that is blanched) After removing the pressure, the blanched area “refills” with blood. After several hours (12 or so, depending on the circumstances), it becomes “fixed”.

9. Differences between livor mortis & Bruise LIVOR MORTIS BRUISE Location Lowest part of the body Any places of the body Pressure Disappear Persistent Swollen + - Cut off Intravascular blood Extravascular blood Intravital sign - +

10. Livor Mortis / post-mortem lividity Character and color of livor mortis: Heart disease  upper chest, neck and face Carbon monoxide, cyanide, other toxins, and extreme cold  bright red discoloration Hydrogen sulfide  green discoloration of livor mortis and internal organ

11. Rigor Mortis Or rigidity  postmortem stiffening of muscles. Transient change  it develops and the disappears After death  ATP is depleted in muscles (since dead cells can no longer produce ATP)  the actin and myosin fibers bind to one another  the entire muscle to become stiff. Muscle stiffen in whatever position they happen to be in at the time of death.

12. Rigor Mortis Goosebumps (cutis anserinus)  the muscles that control the hair on the skin undergo rigor mortis. The skeletal muscle cells continue to break down after death (early onset of decomposition)  the bonds between the actin and myosin fibers break  rigor mortis disappears.

13. Rigor Mortis Onset, peak and dissipation is temperature dependent. Extremely cold environmental temperatures  slow the process. Extremely physically active immediately prior to death  the muscles may be lacking ATP stores  the onset of rigor mortis nearly instantaneous  cadaveric spasm.

14. Algor Mortis Postmortem cooling of the body to equilibrates with its environmental temperature. From the normal living body temperature 37 O C to the cooler environmental temperature. When the environmental temperature exceeds normal body temperature  the dead body temperature will warm up.

15. Other Early Postmortem Changes Skin Skin elasticity  Livor mortis  dark red - purple color Cutis anserious  as the results of the contraction of Mm. Erector Pillae

16. Other Early Postmortem Changes Eyes Cornea reflex to the lights  The corneas become clouded The sclerae if exposed to air (because the eyes are not totally closed)  a dark discoloration within the part that is exposed to air  tache noire (black line). Drying and dark discoloration at the other epithelial surfaces of the body ( the most common locations: lips, tongue, scrotum).

17. Decomposition Autolysis, putrefaction, environmental factors. Autolysis  a body`s own enzymes are acting on itself, causing tissue and cellular destruction (auto=self, lysis=breakdown). Putrefaction  micro-organisms (especially bacteria and fungi) feed on and break down the tissues of a dead body  decomposition fluid

18. Decomposition Environmental factors Heat  increases the decomposition process Animal activity  anthropophagy (animal feeding on a dead body). Physical location of the body  buried in soil, open to air, water  1 week in air = 2 weeks in water = 8 weeks in soil Different types of soil, water, air (humid vs dry)

19. Sign of the Decomposition process Marbling  superficial skin blood vessels become discolored, that similar with marble Skin slippage  the superficial layers of skin become very loose, develop blisters, can slip off the underlying layers The entire body become bloated (because of the decomposition gas production) Purge fluid  red-brown fluid expelled or purged from the mouth, nose and other orifices.

20. Decomposition In extremely moist, warm environments  the fats of the body can undergo saponification (the chemical process of soap formation)  adipocere (characterized by an extremely rancid odor, and the presence of white and yellow, cheesy-appearing aggregates of saponified fats). In an extremely warm but dry environment  mummification (characteristically, the skin takes on a dry, leathery appearance)

21. Mummification Mummification may happen when: Warm / high temperature Dry air condition Continuously air flow A complete mummification process takes about 1 to 3 months

22. Postmortem Injuries Traumatic injury to a body that occurs after death, and generally lacks a “vital tissue reaction” appearance  a yellow color, rather than a red (bloody) color.

23. Time of Death Estimation Postmortem interval (pmi) / time since death Some important sign to estimate the time of death: Livor mortis Algor mortis Rigor mortis Decomposition process Another evidence from the scene and autopsy process

24. Time of Death Estimation obtained on the autopsy process

25. @forensicodontounair