10 Jul 2011

Forensic Pathology

Investigates sudden, unnatural, unexplained, or violent deaths.  Questions a forensic pathologist must attempt to answer:
          -        Who is the victim?
          -        What injuries are present?
          -        When did the injuries occur?
          -        What caused the injuries?
          -        What was the time of death?
If a cause of death cannot be determined by external observation of the body, then an Autopsy is required.
(means to see for oneself)
This a medical dissection of a body to determine cause of death. Causes of death can be classified as:
          -        Suicide
          -        Homicide
          -        Accident
          -        Natural causes
          -        Undetermined
Autopsy cont’d.
        The early stages of decomposition after death involve:
        Rigor mortis: The muscles first relax, then stiffen.  The body becomes rigid. Rigor mortis occurs within 24 hours after death and terminates within 36 hours.
        Livor mortis: Once the heart stops pumping, the blood tends to pool in the parts of the body closest to the ground due to gravity. The skin in these areas appear purplish.  However, skin that was restricted by belts, etc. Will not appear purplish.  This can help determine if the body was moved after death. Livor mortis begins immediately after death and continues for up to 12 hours.

Autopsy cont’d.
        Algor mortis: This is the conditions where the body temperature cools and reaches the ambient or room temperature. The location, size of body, clothing, weather conditions, etc. All play a role in algor mortis.
Generally speaking, beginning an hour after death, the body loses heat at the rate of 1 or 1.5 degrees Fahrenheit per hour until body reaches ambient temperature.
Pallor Mortis

Pallor mortis (paleness of death) is a postmortem paleness which happens almost instantaneously (in the 15-120 minutes after the death) because of a lack of capillary circulation throughout the body. Paleness develops so rapidly after death that it has little to no use in determining the time of death.

Other Autopsy Factors
        Potassium levels in vitreous humor of eye: After death, cells of the inner eye release potassium into the ocular fluid called vitreous humor.  Examining these levels help determine time of death.
        Amount of food in stomach: Can help determine when last meal was eaten.

How long does food take in the GI tract?
50% of stomach contents emptied
2.5 to 3 hours
Total emptying of the stomach
4 to 5 hours
50% emptying of the small intestine
2.5 to 3 hours
Transit through the colon
30 to 40 hours

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