## Mechanism of Death in Hanging **Key Point:** The **most common mechanism of death in hanging is cerebral anoxia due to compression of the carotid arteries**, not asphyxia from tracheal compression. This is a critical distinction that is frequently tested in forensic medicine. ### Mechanisms of Death in Hanging | Mechanism | Frequency | Pathophysiology | Notes | |-----------|-----------|-----------------|-------| | **Cerebral anoxia (carotid compression)** | Most common | Bilateral carotid artery compression → loss of cerebral perfusion | Occurs even with light ligature pressure | | **Asphyxia (tracheal compression)** | Less common | Requires significant downward force; trachea is resilient | Rarely the sole cause | | **Vagal inhibition** | Rare | Sudden stimulation of vagus nerve → bradycardia → cardiac arrest | Requires specific neck compression site | | **Spinal cord injury** | Very rare | Only in judicial hanging with long drop | Not typical in suicidal hanging | **High-Yield:** Carotid artery compression requires **only 2–3 kg of pressure**, whereas tracheal compression requires **15 kg or more**. This is why even a light ligature can be fatal in hanging. **Clinical Pearl:** Loss of consciousness in hanging occurs within **10–15 seconds** due to cerebral anoxia from carotid compression, long before asphyxia from tracheal obstruction becomes significant. **Mnemonic:** **"CAR before AIR"** — Carotid compression (cerebral anoxia) occurs before Airway obstruction (asphyxia) in hanging.
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