In smothering, which of the following is the PRIMARY mechanism of asphyxia?

Explanation

## Mechanism of Smothering **Key Point:** Smothering is a form of asphyxia caused by obstruction of the nose and mouth, preventing the entry of air into the respiratory tract. ### Pathophysiology Smothering involves: 1. Occlusion of both nostrils and mouth by a pillow, cloth, hand, or other object 2. Prevention of air entry into the lungs 3. Rapid depletion of oxygen reserves in the blood 4. Development of hypoxia and hypercapnia leading to death ### Distinguishing Features from Other Asphyxial Deaths | Feature | Smothering | Throttling | Strangulation | |---------|-----------|-----------|---------------| | **Mechanism** | Obstruction of nose/mouth | Compression of neck structures | Ligature around neck | | **Vessels Compressed** | None (airway obstruction) | Carotid/jugular vessels | Carotid/jugular vessels | | **Airway Obstruction** | Yes | No | No | | **Typical Agent** | Pillow, cloth, hand | Hands/forearm | Rope, cord, ligature | **High-Yield:** The key distinction is that smothering causes asphyxia by **blocking the airway entrance**, not by vascular compression or reflex mechanisms. **Clinical Pearl:** Smothering is commonly seen in cases of infanticide, homicide of the elderly, or abuse of incapacitated individuals. [cite:Reddy Forensic Medicine 34e Ch 8]