I. Introduction
- Date and Time of Death
- Why this is important
- Postmortem “clocks”
II. Death is a medical diagnosis
- Pronounced time
- Pronounced vs. Actual
- Prolonged down time
- Hypothermia
- Electrocutions
- “Not dead until they’re warm and dead”
- Advanced decomposition
- Obvious fragmentation of the body
- Decapitation
- Pedestrian vs. Train accidents
III. Algorithm
- The time of death is sometime between the time the person was last seen and the time that he was found. .
- This is the most accurate way of determining the time of an unwitnessed death
- Witnessed deaths are a whole lot easier.
IV. Postmortem clocks
- Rigor mortis
- Livor mortis
- Algor mortis
- Decomposition
- Insect activity
- Gastric contents
V. Rigor mortis
- Skeletal muscle
- fibers actin and myosin
- cross linking and shortening
- Release is an active process requiring ATP
- Chemical process—faster with heat, retarded by cold
2. systemic process
- Occurs all over
- First noticeable in the jaw
- Peaks at 12-24 hours
- Wears off in 48-72 hours
3. “Breaking” rigor
- Not breaking the joint
- Moving against resistance, will break protein cross-links
- Does not recur, but process might have been incomplete
VI Algor mortis
A. Cooling of the body
B. Depends on many factors
- Body habitus
- Clothing
- Ambient temperature
- Fever
- Environmental factors (sun, wind)
C. Timing
- 2-3 hour plateau
- Drops approximately 1.5°/hour (1-3°)
- Reaches temperature of environment
- If environment is hot, the body will be hot as well.
VII. Livor mortis
- Post-mortem pooling of blood
- Lack of circulation, blood under influence of gravity goes to dependent parts
- Heart patients may begin during life.
- Blanching vs. fixed
- Finger pressure will move corpuscles
- Fixed around 12 hours
VIII. Decomposition
- Putrefaction vs. Autolysis
- Putrefaction breakdown by bacteria
- Does not occur in sterile environments
- Maceration
2. Autolysis breakdown by body’s own enzymes
- Most noticeable in RLQ approximately 24-48 hours
- Cecum closest to surface
- Spread of gut bacteria
- Postmortem cultures bloody worthless unless PMI <12 hours
C. Marbling of skin
- Bacteria traveling through vascular tree
- Oxidizing hemoglobin
D. Putrefactive gas formation
- Bacteria make methane, etc.
E. Environment
- 1:2:8 Air, Water, Land
- Dry areas promote mummification
- Wet areas promote adipocere “grave wax”
- a. Mutter Museum
- b. Dead man’s hand
- c. Stinks to high heaven
XI. Bugs
- A. Maggots, flies, beetles
- B. Maggots
1. Fly larvae
2. eggs-larvae-pupae-fly
3. Instar
- C. Flies
1. Blowflies
2. Fleshflies
3. Bluebottles
- D. Beetles
- Dermestid beetles
- Carpet beetles
- E. Wasps
1. Yellowjackets, etc.
X. Gastric contents. Imperfect clock
1. Very dependent on emotional state.
- Rough guide
- 1. Small meal 1-2 hours
- 2. Regular meal 3-4 hours
- 3. Thanksgiving 6-8 hours
XI. Body Disposal Methods
- Burial
- Cremation
1. Forbidden by Orthodox Jews, Muslims, Catholics
2. Samuel–Saul and the Witch of Endor
3. Burial of body parts–resurrection
- Sky Burial
I swear you make me want to go back to school and branch out into the medical-forensics field.
Casey
Comment by Casey — Saturday, 28, August, 2010 @ 11:38 |
I just want to know exactly how Samuel, Saul and the Witch of Endor fit into your lecture.
Comment by Auntie J — Sunday, 29, May, 2011 @ 12:34 |
It involved Jewish burial practices.
Comment by williamthecoroner — Sunday, 29, May, 2011 @ 13:29