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HANGING - Complete PG Exam Notes

Forensic Medicine & Toxicology

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1. DEFINITION

Key distinction: In hanging the constricting force = body weight. In strangulation = external force applied by another person or ligature tightened externally.

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2. TYPES / CLASSIFICATION

A. By Position of Feet (Degree of Suspension)

Exam point: Partial hanging is extremely common - a person can hang themselves kneeling, sitting, or even lying in bed. The weight of the head alone is sufficient to occlude jugular veins (2 kg) and carotid arteries (3.5 kg).

B. By Position of Knot (Typical vs Atypical)

C. By Manner of Death

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3. PRESSURE REQUIRED TO OCCLUDE NECK STRUCTURES

PG High-Yield: The ease of occlusion of jugular veins and carotids (far less than the weight of the head) explains why partial/incomplete hangings are lethal and why NO full suspension is needed for death.

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4. CAUSE OF DEATH

1. Cerebral ischaemia and anoxia - obstruction of carotid arteries (most important)
2. Cerebral congestion - compression of jugular veins causing venous back-pressure
3. Airway obstruction - direct tracheal compression OR root of tongue forced upward/backward blocking pharynx; epiglottis folded over laryngeal inlet
4. Vagal inhibition - pressure on vagus nerve or carotid sinus causing reflex cardiac arrest
5. Spinal cord injury - especially in judicial hanging (fracture-dislocation at C2-C3 level)
6. Combination of above

Key evidence that asphyxia is NOT the primary mechanism:

• Persons with tracheostomy (below the level of noose) have died by hanging
• Vomitus found in bronchi BELOW the ligature level (airway was patent)
• Blood vessel occlusion occurs at far lower pressures than tracheal occlusion

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5. FATAL PERIOD

• Suicidal/non-judicial hanging: 5-8 minutes (common)
• With vagal inhibition: Nearly instantaneous
• Judicial hanging (with cervical fracture): Instantaneous unconsciousness; heart may beat for 8-20 minutes thereafter
• Filmed hanging study (Sauvageau et al.):
  • Loss of consciousness: ~13 seconds
  • Mild convulsions: ~15 seconds
  • Decerebrate posturing: ~19 seconds
  • Loss of muscle tone: ~1 minute
  • Complete cessation of all movement: ~4 minutes

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6. JUDICIAL HANGING

• Convicted criminal; face covered with a dark mask
• Stands on trapdoor; noose placed with knot on the left side of jaw (near chin)
• Trapdoor springs; person falls a calculated distance based on body weight (platform ~5 meters height)
• Sudden violent jerk to neck causes fracture-dislocation at C2-C3 (or atlanto-occipital / atlanto-axial joint)
• Transection of the spinal cord
• Immediate unconsciousness; heart beats 8-20 minutes afterward
• If fall is too short: strangulation (slow death)
• If fall is too long: decapitation
• X-ray shows bilateral fractures of pedicles/laminae of 2nd, 3rd or 4th cervical vertebra
• Associated findings: muscular contractions of facial muscles, twitching/convulsions of limbs, violent respiratory movements of chest

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7. SEQUENCE OF EVENTS / SYMPTOMS (Suicidal Hanging)

• Flashes of light before eyes
• Ringing in ears
• Sudden loss of consciousness
• Convulsive movements
• Death

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8. POSTMORTEM APPEARANCES

A. External Appearances

B. Ligature Mark (THE most important finding)

• Thin hard ligature: narrow, deep, distinct groove
• Rope: mirror-image impression of the twist of rope on skin
• Folded sheet: broad, indistinct furrow
• Rolled cloth: broad, pale furrow
• Along edges: thin line of congestion/haemorrhage at deepest point
• Ligature marks resist decomposition (compressed blood vessels restrict access by putrefying bacteria)
• Ecchymosis with abrasion = strongly suggests antemortem suspension
• The noose typically slips above the larynx, catching under the chin

C. Internal Appearances

• Neck fractures are rare in non-judicial hangings (only ~9-12% of cases)
  • When present: superior horns of thyroid cartilage (most common), hyoid bone
  • Cervical spine fracture: only in obese/elderly with degenerative disease + complete suspension + sudden drop
• Strap muscle haemorrhage: ~20% of cases
• Intimal tear of carotid artery (diagnostic of antemortem hanging)
• Ecchymosis of larynx and epiglottis
• Congestion and oedema of brain, lungs
• Petechial haemorrhages on brain surface, visceral pleura
• Heart: right side distended with dark fluid blood

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9. DIAGNOSIS OF ANTEMORTEM HANGING

1. Antemortem ligature mark with vital reaction (redness, haemorrhage, inflammation)
2. Saliva dribbling mark from angle of mouth
3. Ecchymosis of larynx or epiglottis
4. Intimal rupture of carotid vessels
5. Fracture of thyroid cartilage / hyoid bone (with vital reaction)

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10. MEDICOLEGAL ASPECTS

Suicidal Hanging

• Most common manner
• Room usually bolted from inside
• Suicide note may be present
• No marks of struggle usually
• Lone location chosen
• Common ligature materials: ceiling fan, roof, tree, window

Homicidal Hanging (Lynching)

• Very rare
• Victim must be incapacitated - by:
  • Prior physical assault (look for other injuries)
  • Alcohol or drug intoxication (toxicology screen mandatory)
  • Significant size disparity (adult vs child; strong man vs small woman)
• If victim strangled first and then strung up: ligature mark will be horizontal (not inverted-V) - key differentiating point
• Contusions on arms from forcible restraint may be seen
• Complete toxicological screen and full autopsy mandatory in all alleged suicidal hangings

Accidental Hanging

• Autoerotic asphyxia (sexual asphyxia): deliberately reduces blood/oxygen to brain for erotic pleasure; may accidentally hang themselves; usually males; found in private place; often pornographic material nearby

Key Differentiating Features: Hanging vs Strangulation

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11. SCENE EXAMINATION - KEY POINTS

• Note height of suspension and platform height
• Note pattern of knot (can the person make this knot themselves?)
• Diagrams, photographs, videography
• Never undo/cut the knot except for lifesaving measures - preserve it
• Ground under and around hanging body must be examined
• Check: room bolted from inside? Signs of struggle?
• If rope is cut, recover and preserve all pieces

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12. HIGH-YIELD EXAM MCQ POINTS

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13. ALLIED CONDITIONS TO KNOW

• Bansdola: Form of strangulation using a bamboo stick placed across neck
• Garrotting: Ligature strangulation from behind with sudden jerk
• Mugging: Arm-lock around neck
• Burking: Smothering + compression of chest simultaneously (Burke & Hare)
• Tardieu spots: Petechial haemorrhages from hydrostatic rupture - seen in dependent areas in hanging

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