Unit 4: Asphyxia
4.1 Definition and Types of Asphyxia Deaths
Asphyxia — the oxygen’s deprivation (the life’s smothering): the mechanism’s family — the air’s passage blocked, the oxygen’s exchange prevented, the neck’s vessels compressed. The types (the exam’s list):
- Hanging — the body’s own weight on the ligature (the suspension’s faces: the complete-vs-partial); the knot’s position (the typical occipital — the atypical’s variations); the ligature’s groove (the furrow’s direction: the upward-inverted-V).
- Strangulation — the external force on the neck (the ligature (the horizontal groove — the hanging’s differential!) and the manual (the finger-marks — the bruises’ ovals)).
- Suffocation — the environment’s oxygen lack (the smothering (the obstruction: the pillow, the hand); the choking (the internal: the food, the foreign body); the confined-space (the gases)).
- Drowning — the water’s drowning (the fresh-vs-salt faces; the “dry drowning” debates).
- The mechanical (traumatic) asphyxia — the crush (the chest’s compression — the disaster’s-and-crowd’s deaths).
- The chemical asphyxiants — the gases (the carbon-monoxide, the cyanide — the toxicology’s bridge).
4.2 Mechanism of Death in Asphyxia
The physiology’s sequence: the oxygen’s lack → the unconsciousness (the minutes’ window) → the brain’s irreversible damage → the death. The neck-compression’s special mechanism (the exam’s duo): the vessels’ occlusion (the carotids — the quick unconsciousness) vs the airway’s closure (the slower suffocation) + the vagal inhibition (the reflex’s sudden death — the “one-blow” hanging lore). The autopsy’s signs (the classic general signs): the cyanosis; the petechiae (the conjunctival haemorrhages — the small red spots); the congestion-and-oedema; the fluidity of blood — the signs’ caution (the non-specificity: the asphyxia’s signs in the other deaths too — the diagnosis by the type’s specific signs (the furrow, the grip-marks) + the circumstances).
4.3 Manner of Death in Asphyxia
The manner’s determination (the exam’s forensic core):
- The hanging’s manner: the suicide’s typical (the scene’s: the note, the access, the hesitation’s faces) vs the homicides-disguised-as-hanging (the post-mortem suspension — the ligature’s differential: the furrow’s depth-and-direction; the victim’s lifting); the accidental hangings (the auto-erotic’s tragic faces).
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