Forensics Overview





Cause of death

Disease or injury that produces the physiological changes that result in death

MI due to ASCVD

Manner of death

How the cause of death occurred

natural, homicide, suicide, accident, undetermined

Mechanism of death

physiological event set in motion by the cause of death

cardiorespiratory arrest


superficial scrape



tearing injuries (occur over bony prominences)



bruising; tearing of blood vessels and bleeding into tissues



red, dendritic mark on skin (electrical injury)



Major considerations for time of death: livor, rigor, body temperature, vitreous analysis, stomach contents, surrounding environment


Livor Mortis

- settling of blood in dependent areas due to gravity

- areas with pressure do not develop livor

- noticeable within 30 minutes of death

- mimics bruising


Rigor Mortis

- stiffening of muscles

- after 2 hours (peaks at 12h, ends at 24h)

- develops more quickly in hot environment, lasts longer in cold environments

- small muscles affected first



·          result of skin necrosis

·          green discoloration in lower abdomen (intestine closest to skin)

·          marbling (bacterial growth along vessels)

·          bloating of face and head (slipping skin – hand comes off in glove - , blister formation)

·          gas production ŕ rectal prolapse, eyes bulging, tongue protruding


Who gets referred to the medical examiner

1.        Death under suspicious, unusual, or unnatural circumstances

a.        Sudden violence (car accident, murder, etc.)

b.        Suicide

c.        Casualty

d.        Suddenly when in apparent health

e.        Found dead (death unattended by physician)

f.         In prison

g.        Cremation

h.        Lack of 24 hour rule (hospitals may have, state does not require)

i.         SIDS (happens most commonly 2-4 months of age) Defined as:

                                                               i.      diagnose ONLY if under 1 year and unexplained after:

1.        complete autopsy

2.        examination of death scene

3.        review of clinical history

                                                              ii.      SIDS mimics

1.        positional asphyxia

2.        down in bed with mother, father, pets, comforters etc.

3.        dies in presence of non-biological relative (boyfriend, etc.)

4.        shaken baby, damage head (no external marks)




A number of manners of death were discussed (blunt force, asphyxia, thermal injuries, etc.); most of these are “common-sense” with a few notes listed below:


Best estimate of time of death: time last seen alive

CO toxicity: liver is red

Cardiac tamponade: fatal if rapid; tolerated to a certain extent if slow

SIDS: diagnosis of exclusion (2-4 months old)

Burns: 1st degree: epidermis (sun-burn); 2nd degree: epidermis and dermis (blisters); 3rd degree: full-thickness (no sensation, scarring); 4th degree: charring

Drowning: salt vs. fresh water (water flow differs in alveoli)

Methanol toxicity: acidosis, headache, blindness (treatment = ethanol)

Gun wounds: Entrance and exit wounds can be difficult to determine (exit wounds tend to be more irregular and larger)