1. Manner, Mechanism, Cause and Time of Death

2. How do we define Death? Death - An individual who has sustained either (1) irreversible cessation of circulatory and respiratory functions, or (2) irreversible cessation of all functions of the entire brain, including the brain stem is dead. Death is a process not an event –Physiologists; when the heart stops beating, the cells begin to die and: O 2 levels drop Basic processes of the body fails –Nerves, muscles, organs stop working, Stoppage Once enough cellular death occurs life cannot restart

3. Forensic Pathologist a sub-specialty of pathology that focuses on determining the cause of death by examining a corpse. Autopsy - a postmortem examination to discover the cause of death or the extent of disease. Autopsy's are normally are called upon when the death is: –Sudden –Violent –Unexplained Investigators will look into –Manner –Mechanism –Cause –Time

4. Manner of Death 1.Natural Interruption and failure of bodily function resulting from age or disease 2.Accidental Unplanned event 3.Suicidal A person purposely kills oneself 4.Homicidal Death of one person caused by another 5.Undetermined Suicidal or accidental –Pills, guns

5. Mechanism of Death The physiological dysfunction that results in the death. Example: death due to the gunshot wound, the mechanism is exsanguination (extreme blood loss).

6. The disease or injury that produces the physiological disruption inside the body resulting in death. Example: a gunshot wound to the chest. Cause of Death

7. Estimating Time of Death 1. Algor mortis: reduction in body temperature following death 2.Rigor mortis: stiffening of the body after death 3. Livor mortis: (Lividity) : settling of the blood in the lower portion 4.Potassium levels in vitreous humor + Clouding of the cornea 5. Digestive Contents 6. Evidence of Decompositional Process 7. Presence/absence of purge fluids 8. Drying of the tissue 9. Insect Larval Instars

8. Algor Mortis Uses body temperature to determine time of death Normal body temperature is 37 0 C (98.6 0 F) A body loses heat at a rate of 1.4 0 C per hour until the ambient temperature is reached –Rate varies according to environmental temperature Once ambient temperature is reached, you cannot use this method to determine time of death

9. Question: What are some Factors that would affect Algor Mortis? Ambient temperature Wind? Excess body fat? Clothing

10. Rigor Mortis TimeEventAppearance 2-6 hoursRigor beginseyelids, Jaws stiffen After 2 -6 hours then center of body stiffens 12 hoursComplete RigorEntire body rigid 15-36Slow loss of rigor, small muscles first Lost in head and neck, last is bigger leg muscles 36-48Rigor disappears, muscles become relaxed

11. Rigor mortis ? What are some factors affecting Rigor mortis ? 1.Ambient temperature, Cooler the body the slower the onset of rigor 2.Person’s weight Fat stores more oxygen and slow rigor 3. Type of clothing Helps keep the body warm

12. 3. Livor mortis

13. Livor mortis the condition that occurs after death and results in the settling of blood in areas of the body closest to the ground –Evident 30-120 minutes postmortem –8-12 hours (24-36 hours in cooler temps) postmortem- maximum color or “fixed” livor mortis due to hemolysis (blood vessels break down) –May occur antemortem (before death) in slow deaths –Can congest internal organs –Discoloration does not occur in the areas of the body that are in contact with the ground or another object –

14. Clouding of the cornea Cornea is the clear covering of your eyes –Becomes cloudy and opaque after death Takes only a few hours after death if eyes are open at death It takes 24 hours if eyes are closed at death. Cornea

15. Digestive Contents Stomach empties contents after 4-6 hrs Small intestine empties after 24 hrs Colon empties 24-48 hrs

16. Stages of Decomposition 2 days –Cells autolysis –Greenish purple staining occurs, blood decomposing –Skin takes on Marbled Appearance 4 days –Skin blisters –Abdomen swells with carbon dioxide Due to bacteria in intestines 6-10 days –Corpse bloats with CO2 –Corpse eventually bursts –Fluid begins leaking from openings as cell membranes rupture –Eyeballs liquefy –Skin sloughs off

17. Forensic entomology Entomology is study of insects

18. Life cycles of insects are used to determine time of death Complete metamorphosis adult, egg, larva (maggot), pupa, adult

19. Complete Metamorphosis 23 hrs 35 hrs 50 hrs 72 hrs 130 hrs 143 hrs

20. Blowflies are usually the 1 st invader Can lay eggs within 20 minutes of death

21. Beetle larvae

22. Predacious beetles