William The Coroner’s Forensic Files

Friday, 27, August, 2010

Graduate School 3#

Filed under: Forensics,Teaching — williamthecoroner @ 15:38

I.          Introduction

  1. Date and Time of Death
  2. Why this is important
  3. Postmortem “clocks”

II.         Death is a medical diagnosis

  1. Pronounced time
  2. Pronounced vs. Actual
  3. Prolonged down time
  • Hypothermia
  • Electrocutions
  • “Not dead until they’re warm and dead”
  1. Advanced decomposition
  2. Obvious fragmentation of the body
  • Decapitation
  • Pedestrian vs. Train accidents

III.       Algorithm

  1. The time of death is sometime between the time the person was last seen and the time that he was found.            .
  2. This is the most accurate way of determining the time of an unwitnessed death
  3. Witnessed deaths are a whole lot easier.

IV.       Postmortem clocks

  1. Rigor mortis
  2. Livor mortis
  3. Algor mortis
  4. Decomposition
  5. Insect activity
  6. Gastric contents

V.        Rigor mortis

  1. 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

    1. Body habitus
    2. Clothing
    3. Ambient temperature
    4. Fever
    5. Environmental factors (sun, wind)

      C.        Timing

      1. 2-3 hour plateau
      2. Drops approximately 1.5°/hour (1-3°)
      3. Reaches temperature of environment
      4. If environment is hot, the body will be hot as well.

      VII.      Livor mortis

      1. Post-mortem pooling of blood
      2. Lack of circulation, blood under influence of gravity goes to dependent parts
      3. Heart patients may begin during life.
      4. Blanching vs. fixed
        1. Finger pressure will move corpuscles
        2. Fixed around 12 hours

      VIII.     Decomposition

      1. Putrefaction vs. Autolysis
        • Putrefaction breakdown by bacteria
        • Does not occur in sterile environments
          1. 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

      1. Bacteria traveling through vascular tree
      2. Oxidizing hemoglobin

      D.        Putrefactive gas formation

      1. Bacteria make methane, etc.

      E.         Environment

      1. 1:2:8 Air, Water, Land
      2. Dry areas promote mummification
      3. 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
      1. Dermestid beetles
      2. 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

      1. Burial
      2. Cremation

      1.         Forbidden by Orthodox Jews, Muslims, Catholics

      2.         Samuel–Saul and the Witch of Endor

      3.         Burial of body parts–resurrection

      1. Sky Burial
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      3 Comments »

      1. 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 | Reply

      2. 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 | Reply

        • It involved Jewish burial practices.

          Comment by williamthecoroner — Sunday, 29, May, 2011 @ 13:29


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