Forensic Pathology and Autopsy
Overview
This domain tests the logic of death investigation: distinguishing cause, mechanism and manner, interpreting postmortem change, and recognizing injury patterns that carry legal consequences.
Core rules
- Cause, mechanism, manner: cause is the disease or injury that initiated the fatal process; mechanism is the pathophysiologic derangement (arrhythmia, exsanguination, cerebral edema); manner is natural, accident, suicide, homicide or undetermined.
- Postmortem change: livor mortis (dependent fixation, about 2–4 hours onward), rigor mortis (begins in small muscles, resolves over roughly 24–48 hours), algor mortis, and decomposition are used for a time-of-death estimate with wide confidence limits.
- Asphyxia: petechiae of conjunctivae and face, cyanosis, and ligature or hand marks on the neck; hyoid and thyroid cartilage fractures suggest pressure.
- Gunshot wounds: entrance wounds show a marginal abrasion collar; exit wounds are typically larger and irregular without a collar; soot, tattooing and powder embeds indicate close-range firing.
- Autopsy types: hospital (clinical) autopsies require consent; medicolegal autopsies are ordered by legal authority and do not.
Worked example
A body is found with a small circular wound with an abrasion collar on the chest and a larger irregular wound on the back, no soot on the skin. Reasoning: the chest wound is the entrance, the back wound the exit, and absence of soot places the muzzle beyond close range. The manner must be determined from scene and investigation, not from wound morphology alone.
Traps
Stating manner of death when only the cause is established. Using rigor mortis alone to time death. Missing that a hospital autopsy needs consent while a medicolegal one does not. Over-interpreting soot as proof of homicide.