1. Meaning, Manner, Mechanism, Cause, and Time
Death
Meaning, Manner, Mechanism, Cause, and Time

2. Forensic Entomology Flies arrive within 10 minutes of death
Fly predators such as wasps arrive within 3-7 days
Ants, cockroaches, and beetles arrive within 8-18 days

3. Insects are ectothermic-body needs to be warmed by outside to be able to grow
Will speed up process in hot climates/slow in cold regions
Drugs – cocaine will speed up life cycle
Drugs – poisons (arsenic) will slow down

4. Back in the day…
17th century: anyone in a coma or with a weak heartbeat was presumed dead & buried
People had a fear of being buried alive.
There were “waiting mortuaries”

5. Meaning of Death End of life
“Irreversible cessation of circulation of blood”
Brain activity stopped
Cells begin to die, known as cell autolysis

6. Medical Examiner vs Coroner
Medical examiner (M.E.)
Medical doctor who conducts examination on deceased
Conducts autopsy (post-mortem)
Coroner
An elected position.
Can not perform an autopsy

7. the cause, the mechanism, and the manner of death.
When a death occurs, the medical examiner must fill out a death certificate.
In order to properly complete this document, they must determine three things:
the cause,
the mechanism,
and the manner of death.

8. There is often confusion about which is which.
The cause of death is the disease or injury that produces the physiological disruption inside the body resulting in death
For example, a gunshot wound to the chest.
The mechanism of death is the physiological derangement that results in the death.
An example of a mechanism of death due to the gunshot wound described above is exsanguination (extreme blood loss).

9. Manner of death Cause of death Mechanism of death Time of death
Category
Event leading to death
Specific body failure
When they died
Manner of death
Cause of death
Mechanism of death
Time of death

10. Manner of Death Natural Accidental Suicidal Homicidal Undetermined
Interruption and failure of body functions resulting from age or disease
Caused by unplanned events
Purposefully killing oneself
Caused by another person; murder

11. Quick Check!!!!
A man with a heart condition is attacked and dies from a heart attack during the assault. Is the MOD accidental or homicide?
An elderly woman dies after being kept from receiving proper health care by her son. Is the manner of death natural or homicide?

12. Cause of Death (COD) Natural causes
Heart disease
Cancer
Stroke
Respiratory Disease
Accidents

13. Cause of Death (COD) Homicide/Suicide
Poisoning
Hanging
Drowning
Shooting

14. Mechanism of Death (specific body failure)
Cause:
Shooting
Strangulation
Drug Overdose
Mechanism:
Exsanguination (bleed to death)
Asphyxiation (lack of oxygen)
Hypoxia (lung failure)

15. Factors to Determine Time of Death (TOD)
Changes of the eye
Stages of decomposition
Insects (forensic entomology)
Livor Mortis
Rigor Mortis
Algor Mortis
Stomach and intestinal contents

16. Time of Death (TOD) Livor mortis Rigor mortis Algor mortis
Death color – pooling of blood in tissues after death (lividity)
Death stiffness – stiffening of skeletal muscles after death
Death heat – cooling of body after death

17. Livor Mortis Lividity: pooling of blood in body
Begins 2 hrs. after death
Caused by the break down of red blood cells
2-8 hrs.: color disappears when skin is pressed
>8 hrs.: permanent discoloration

18. Livor Mortis The ambient temp affects time for lividity to set in
Hot, summer day – blood pools faster
Cool room: slower process
Can determine if body was moved
Dual Lividity

19. Rigor Mortis
Cause: no oxygen to cells  calcium buildup  muscle fibers remain contracted
Starts 2 hrs. after death
Starts and stops from head  legs
12 hrs: most rigid
Stiffness disappears completely after 36 hrs.

22. Factors affecting rigor mortis:
Ambient temperature
Person’s weight
Type of clothing
Illness
Level of physical activity shortly before death
Sun exposure

23. Algor Mortis Literally means DEATH HEAT Temperature loss in a corpse
Thermometer inserted in liver
1 hr. after death: cools 1.4°F per hour
1-12 hrs: cools 0.7°F per hour until it reaches surrounding temperature

24. Factors affecting algor mortis:
Environment – lose heat faster (cold), lose heat slower (hot)
Wind – more wind  fast heat loss
Excess body fat – slows heat loss
Clothing – slows heat loss
Rule of thumb: 1°F per hour

25. Stomach and Intestinal Contents
TOD 0-2 hours after last meal: undigested stomach contents present
TOD 4-6 hours after meal: stomach empty, food in small intestine
TOD 12+ hours after meal: waste in large intestine

26. The eye after death
A thin film starts to develop minutes after death on the surface of the eye
Called a corneal film

27. Stages of Decomposition
0-2 Days:
Cell autolysis
Flies lay eggs on corpse
Green, purplish staining
Skin: marbled appearance
Face discolored

28. Stages of Decomposition
4 Days:
Skin blisters
Abdomen swells (CO2 gas released by bacteria in intestines)
Maggots on corpse

29. Stages of Decomposition
6-10 Days:
Corpse bloats with CO2, chest and abdomen burst and collapse
Fluids leaks from body openings
Eyeballs and other tissues liquefy
Skin sloughs off
More eggs,
maggots, flies,
and beetles

30. Stages of Decomposition
10-20 Days:
Bloated body collapses
Flattened body, creamy flesh
Strong smell of decay
Fluids drain and seep
Days:
Body dry; decays slowly
Hair disappears, leaving bones