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

2. Is a person with a heartbeat alive even if there is no brain activity?
How Do we Define Death?
Is a person with a heartbeat alive even if there is no brain activity?

3. How do we define Death? Death is a process not an event
Physiologists; when cells begin to die
O2 levels dropno ATP
Basic processes of the body fails
Nerves, muscles, organs stop working…
Once enough cellular death occurs life cannot restart

4. Forensic Pathologist Examination of the deceasedAutopsy
when the death is:
Sudden
violent
unexplained deaths
Investigators will look into
Manner
Cause
mechanism of death
Questions sought to answer:
Who is the victim
What injuries are present
When did the injuries occur
Why and how were the injuries produced

5. Manner of Death Natural Accidental Suicidal Homicidal Undetermined
death resulting from age or disease
Accidental
Unplanned event
Suicidal
Intentionally killing oneself
Homicidal
Death of one person caused by another
Undetermined
Suicidal or accidental??
Pills, guns

6. Cause and Mechanism Cause of death Reason someone dies:
Heart attack, gunshot, infection, disease
Mechanism of Death-body failure
Loss of blood (exsanguination)
Loss of oxygen (asphxia)

7. Time of Death

8. Estimating Time of Death
Rigor mortis-Stiffness of Death
Livor mortis: (Lividity)-Color of Death
Algor mortis: Body Core Temperature
Potassium levels in vitreous humor + Clouding of the cornea
Stomach Contents
Evidence of Decomposition
Insect

9. Algor Mortis body temperature Normal body temperature is 370C (98.60F)
A body loses heat at a rate of 1.40F per hour until the ambient temperature is reached
(Rate varies)
Once ambient temperature is reached, you cannot use this method to determine time of death

10. Question: What are some Factors that would affect Algor Mortis?

11. Rigor mortis: The stiffness begins 2 hours after death
Oxygen is needed for muscle relaxation. 11 11

12. Rigor Mortis Time Event Appearance 2-6 hours Rigor begins in head
eyelids, Jaws stiffen
After 2 hours
then center of body stiffens
12 hours
Complete Rigor
Entire body rigid
15-36
Slow loss of rigor, small muscles first
Lost in head and neck, last is bigger leg muscles
36-48
Rigor disappears, muscles become relaxed

13. Figure 49.31 The structure of skeletal muscle13

14. What are some factors affecting Rigor mortis ?
Ambient temperature,
Cooler the body the slower the onset of rigor
Person’s weight
Fat stores more oxygen and slow rigor
Type of clothing
Helps keep the body warm
Illness
Dies with a fever? What would you expect?
Hypothermic? What would you expect?
Level of physical activity
Struggling before death rigor, What would you expect?

15. Livor mortis
* Lividity -settling of the blood in the lower portion of the body
*** Discoloration does not occur in the areas of the body that are in contact with the ground or another object
Begins 2 hours after death and permanent after 8 hours
Dual lividity-indicates a change in position prior to becoming fixed

16. 3. Livor mortis

17. Potassium levels 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.

18. Digestion provides clues
*stomach empties around 4-6 hours after last meal
*If NO food is in stomach-how long ago did death occur?
*small intestines empties after approx. 24 hours after last meal
*large intestines empties after approx after last meal

19. Stages of Decomp

20. Stages of Decomposition
Initial decay
Corpse appears normal, internal bacterial decay and autolysis begins
Putrefaction
Odor of decaying corpse swollen
Black Putrefaction
Very strong odor, flesh appears black, gases escape, corpse collapses
Butyric Fermentation-drying,cheesy smell
Dry Decay
Bone and Hair. (without water, limited bacterial action)

21. Stages of Decomposition
2 days
Cells autolysis-cell death
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

22. Forensic entomology Entomology is study of insects
Used for a large variety of instances
Insects and human remains
Damage to property for a civil suit
Insects and injuries in abuse cases

23. Life cycles of insects is important to understand time of death
* complete metamorphosis (egg, larva, pupa, adult)
Fly larva are called maggots
Determining stages will help tell time of death

25. Complete Metamorphosis25

26. Fly Pupa
                                         26

27. Adult fly emerging from pupa
                                          27

28. Blowflies are usually the 1st invader
                                         
Can lay eggs within 20 minutes of death
                                28

29. Other uses of Insects
Can do DNA analysis on the victim ingested by insect
Can do toxicological analysis
Wound location

30. Types of Injury Antemortem-before death. Signs of healing
Perimortem-near time of death. No healing
Postmortem-after death. Discolored,bones break easier(bite marks, crushing)