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POSTMORTEM INTERVAL (PMI) :!!: - Coggle Diagram
POSTMORTEM INTERVAL (PMI)
:!!:
Methods of determining PMI
Livor mortis
Reddish, purlish-blue discoloration
Due settling of blood in vessels on dependent area of the body
In area pressed on hard surface, blood cannot settle -> pale discoloration
Rigor mortis
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Refers to the stiffening of the body observed after death due to postmortem muscle contraction
it usually takes 6 to 12 hours to develop a full rigor mortis.
Temperature of the body (algor mortis)
most common for accurately determine time of death
it is incorrect to assume that everyone has normal body temperature
oral body temp normal subject: 35.5-38.2
vary diurnally, low in morning, high in the evening
normal temp in women is higher
strenuous exercise, CHF cause higher temp
body cooling follows phases and factors influencing it
Body mass/ surface area ratio
Ambient temp and climate condition
Clothing, covering
Surface that the body lying
Stomach content
It's the time since the last meal
Timeline:
-Undigested (solid food still identifiable) : <1-2 hrs
-Partially digested (chyme forming) : 2-4 hrs
-Empty stomach : >4-6 hrs
These are approximatiion and not reliable enough to use in isolation for PMI.
Environmental factors
Entomology
Invasion of unprotected body by sarcocaprophagos insect
Corneal changes
Corneal clouding begins ~ 2hrs if eye are open; delayed if closed.
Tache noise appears within 3 to 4 hrs in exposed sclera
These are supportive signs of early PMI (within 24 hrs) but must be correlated with rigor, liver and algor mortis.
IMPORTANCE
Guides autopsy and toxicology accurately especially drug- related deaths or infections
helps to determine how much body has changed since death like cooling or decomposing. Hence, helps to estimate time of death more accurately
Assist in criminal investigations
Estimating time of death accurately is needed for inheritance, insurance claims and life policies.
To establish time of death
Definition
= Time since death, Estimated via observable postmortem changes
