Hanging, Strangulation & Throttling

Asphyxial deaths from pressure on the neck are a perennial NEET PG favourite from Forensic Medicine. The central medico-legal skill is to read the ligature mark, the petechiae, the neck structures, and the scene — and from these decide whether you are looking at a suicidal hanging or a homicidal strangulation. This note builds that decision tree carefully.

Definitions and classification

Violent asphyxial deaths are deaths from mechanical interference with respiration. Pressure-on-neck deaths form one major group:

• Hanging — suspension of the body by a ligature around the neck, where the constricting force is the weight of the body itself (or part of it). The body need NOT be fully suspended.
• Strangulation — constriction of the neck by a force other than the body weight.
  • Ligature strangulation (bansdola, garrotting) — by a cord/rope tightened by hand or mechanical means.
  • Manual strangulation = Throttling — constriction by the assailant's hands/fingers/forearm.
  • Mugging — neck held in the bend of the elbow (forearm) from behind.
  • Palmar strangulation / Bansdola — neck compressed between two sticks/bamboos.
• Choking — obstruction within the air passages (e.g. a bolus). (Inner asphyxia.)
• Smothering, gagging, café coronary — related obstructive asphyxia, distinct from neck pressure.

High-yield: In hanging the weight of the body acts as the constricting force; in strangulation an external force other than body weight does the constriction. This single distinction underlies almost every MCQ.

Types of hanging

Type	Position of knot / suspension	Notes
Typical hanging	Knot at occiput (nape of neck), symmetrical	Compression of carotids + vertebral arteries → fastest cerebral anoxia
Atypical hanging	Knot anywhere else (side/front)	Commonest in real life; mark runs obliquely
Complete hanging	Body fully suspended, no part touches ground	—
Partial / incomplete hanging	Part of body touches ground (sitting, kneeling, lying)	Even body parts' weight can hang; <15–20 kg force can be fatal

High-yield: Hanging can occur with the feet touching the ground (partial hanging) — a body need not be fully suspended. Examiners love this because it counters the lay assumption.

Mechanism / pathophysiology of death in hanging

Death is rarely from simple airway occlusion alone. Multiple mechanisms operate, in this approximate order of importance and speed:

1. Cerebral anoxia from vascular occlusion — the carotid arteries are occluded by ~5 kg, the jugular veins by ~2 kg, the trachea by ~15 kg, and the vertebral arteries by ~30 kg. Even partial weight occludes carotids → rapid loss of consciousness.
2. Venous congestion — if only veins occlude (face becomes congested, cyanosed).
3. Vagal inhibition / reflex cardiac arrest — pressure on carotid sinus/sheath → bradycardia/asystole → instantaneous, pale death (Fagal/reflex death).
4. Airway occlusion — tongue pushed up against posterior pharyngeal wall.
5. Cervical cord injury — in judicial hanging, a long drop fractures/dislocates C2 (hangman's fracture, fracture-dislocation of C2 over C3) → instantaneous death.

Flow of fatal events in suicidal hanging: ligature tightens → carotid/jugular occlusion → cerebral anoxia → loss of consciousness in ~10–15 s → convulsions → respiratory arrest → cardiac arrest over a few minutes.

High-yield: The most common mechanism of death in hanging is cerebral anoxia from venous and arterial (carotid) occlusion, NOT asphyxia from airway block. Pure airway occlusion needs ~15 kg — far more than carotid occlusion.

The ligature mark — the single most examined sign

This is the crux of differentiating hanging from strangulation.

Feature	Hanging	Ligature strangulation
Direction of mark	Oblique, runs upward toward knot	Horizontal / transverse, encircles neck
Level	High up, above thyroid cartilage, near chin/larynx	Low, at or below thyroid cartilage
Continuity	Non-continuous / incomplete (gap at site of knot)	Continuous, completely encircles neck
Base of groove	Dry, hard, parchment-like, pale/yellow-brown	Soft, may be reddish, less parchmented
Salivary dribble	Present (from angle of mouth, away from knot side)	Absent
Pattern impression	Less marked	Often patterned (rope weave) clearly seen

High-yield mnemonic for hanging mark: "HOIDN" — High, Oblique, Incomplete, Dry (parchmented), Non-continuous. Strangulation mark = low, transverse, continuous, soft.

High-yield: A dribble of saliva running down from the angle of the mouth on the side opposite the knot is diagnostic of antemortem hanging — it is a vital sign that cannot be produced after death and cannot be simulated.

External findings

Hanging

• Face is usually pale (typical hanging — carotids occluded) OR congested/cyanosed with petechiae (if only veins occlude, e.g. atypical/partial).
• Tongue protruded, often dark, dry.
• Hands clenched; postmortem lividity in legs/forearms, genitals (dependent parts in upright suspension) — distal lower limbs show "glove and stocking" hypostasis.
• Seminal/urinary/faecal emission may occur.
• Dribble of saliva (vital sign).
• Eyes: usually closed or partly open; petechiae less common in typical hanging.

Strangulation

• Face congested, cyanosed, swollen, with abundant petechial haemorrhages (Tardieu spots) in eyelids, conjunctivae, face, behind ears.
• Bleeding from nose/ears/mouth possible.
• Signs of struggle / defence injuries, disturbed scene.
• Ligature mark low and transverse.

High-yield: Tardieu spots = petechial haemorrhages of asphyxia (eyelids, conjunctivae, pleura, epicardium). They are far more florid in strangulation/throttling than in typical hanging, because in hanging the carotids are usually occluded preventing congestion.

Internal neck findings

Structure	Hanging	Strangulation	Throttling
Hyoid bone fracture	Greater cornu, older age, esp. in elderly	Less common	Common
Thyroid cartilage	Less commonly fractured	Superior horns may fracture	Fractured
Cricoid	Rarely	May fracture	May fracture
Subcutaneous bruising / muscle haemorrhage	Usually minimal	More	Marked, deep
Carotid intimal tear (Amussat's sign)	May be present (transverse intimal tear)	—	—

High-yield: Hyoid bone fracture is more common in older individuals (after ossification of the greater cornu, usually >40 yrs) and is commonest in throttling/manual strangulation, but can occur in hanging too. It is NOT pathognomonic of homicide. The superior horn of the thyroid cartilage is the cartilage most often fractured.

Named neck signs to memorise:

• Amussat's sign — transverse tear in the internal coat (intima) of the carotid artery in hanging.
• Brouardel's sign — petechial haemorrhages / ecchymoses in subcutaneous tissue and muscles around the ligature.
• Sehrt's sign — small tears in the intima of carotid (some texts equate with Amussat).
• Lemon-yellow parchment base of the groove in hanging.

Throttling (manual strangulation) — distinctive features

Throttling is always homicidal (you cannot throttle yourself — loss of consciousness releases the grip).

External marks reflect the hand:

• Disc-shaped bruises from finger pads.
• Crescentic abrasions / nail marks from fingernails.
• If the assailant uses the right hand from front, more marks lie on the right side of the victim's neck (and vice versa) — examiners test this orientation logic.
• Deep bruising of strap muscles; hyoid and thyroid fractures common.

High-yield: Throttling is invariably homicidal — self-throttling is impossible because unconsciousness relaxes the grip and pressure is lost.

Mugging / Bansdola

• Mugging — forearm across the neck from behind; few external marks, deep internal bruising.
• Bansdola — neck compressed between two hard sticks/bamboo; two parallel marks (one front, one back).

Diagnosis & investigations of choice

The diagnosis is essentially autopsy-based. Key autopsy steps and adjuncts:

1. Bloodless dissection of the neck (layer-by-layer) — done last, after draining cranial and other vessels, to avoid artefactual congestion that mimics bruising.
2. Subhyoid / retropharyngeal dissection for deep muscle haemorrhage.
3. Histopathology of the ligature mark — to confirm vital reaction (antemortem): congestion, vesication, leucocyte infiltration, fibrin.
4. Radiology / CT of neck — to document hyoid and laryngeal cartilage fractures (modern adjunct; virtopsy).
5. Diatom test if drowning is a differential.

High-yield: Always confirm whether the mark is antemortem (vital reaction present) or postmortem (a body hanged after death to simulate suicide). Vital signs = salivary dribble, ecchymosis in the groove (Brouardel), congestion, leucocytic infiltration histologically.

Differentiating antemortem from postmortem hanging

Antemortem hanging	Postmortem hanging (body hanged after death)
Salivary dribble present	Absent
Mark: parchmented, ecchymosed base, vital reaction	Soft, no vital reaction
Petechiae, congestion in appropriate distribution	Mismatched with lividity
Lividity consistent with suspended posture	Hypostasis elsewhere → mismatch reveals the body was moved

Suicidal hanging vs homicidal strangulation — the master comparison

Point	Suicidal hanging	Homicidal strangulation
Ligature mark	High, oblique, incomplete, dry	Low, horizontal, continuous
Knot	Usually fixed/slip knot, accessible	—
Saliva dribble	Present	Absent
Face	Often pale (typical)	Congested, petechiae
Neck deep injury	Usually little	Marked muscle bruise, fractures
Scene	Suicide note, locked room, footstool, fibres on hands	Disturbed, signs of struggle
Defence wounds	Absent	Often present
Hyoid/thyroid #	Less	More

High-yield: Hanging is almost always suicidal; ligature strangulation is usually homicidal; throttling is always homicidal. Accidental hanging occurs in children/autoerotic asphyxia.

Special scenarios

• Judicial hanging — long drop (the "drop" calculated by body weight; ~1372 ft·lb of energy). Causes fracture-dislocation of C2 (hangman's fracture) and transection of cord → instantaneous death; knot placed at sub-mental / under the angle of the jaw to throw the head back.
• Autoerotic / sexual asphyxia — accidental hanging during masturbatory hypoxyphilia; partial suspension, escape mechanism present, pornographic material, padding under ligature, cross-dressing, mirror.
• Lynching — homicidal hanging (rare).
• Café coronary — sudden death during eating from a bolus impacting the larynx (vagal); mimics MI; NOT neck pressure but classic asphyxia MCQ.

Complications in survivors of near-hanging / strangulation

• Hypoxic-ischaemic encephalopathy, cerebral oedema.
• Aspiration pneumonia, ARDS, non-cardiogenic pulmonary oedema ("postobstructive").
• Laryngeal oedema, airway obstruction.
• Cervical spine / carotid artery injury, dissection, delayed stroke.
• Anoxic seizures, persistent vegetative state.

Key differentials

• Hanging vs ligature strangulation — mark direction/level/continuity (table above).
• Strangulation vs natural petechiae — petechiae also in coughing, CPR, crush asphyxia.
• Hyoid fracture: antemortem vs postmortem artefact — antemortem shows haemorrhage at fracture site.
• Hanging vs drowning (body recovered from water) — diatom test, froth, washerwoman's hands.
• Ligature mark vs postmortem changes — e.g. a tight collar groove, decomposition.

Recently asked / exam angle

• "Which structure occludes at the least weight in hanging?" → Carotid arteries (~5 kg) — jugulars ~2 kg; trachea ~15 kg; vertebrals ~30 kg. (Order frequently asked.)
• "Amussat's sign is seen in?" → Carotid intimal tear in hanging.
• "Most common mechanism of death in hanging?" → Cerebral anoxia (asphyxia + venous congestion), not pure airway obstruction.
• "Salivary dribble indicates?" → Antemortem hanging (vital sign).
• "Throttling is which manner of death?" → Homicidal (always).
• "Hyoid fracture is most common in?" → Manual strangulation/throttling, and in older individuals.
• "Knot position in judicial hanging?" → Below the angle of the jaw / sub-mental to cause C2 fracture.
• "Tardieu spots are seen prominently in?" → Strangulation / asphyxial congestion.
• "Ligature mark in strangulation is?" → Low, horizontal, continuous, soft.
• Image-based MCQs showing a neck photograph asking hanging vs strangulation — apply HOIDN.

Rapid revision

1. Hanging = body weight is the constricting force; can be partial (feet on ground).
2. Hanging mark: High, Oblique, Incomplete, Dry, Non-continuous (HOIDN).
3. Strangulation mark: low, transverse/horizontal, continuous, soft.
4. Carotid occludes at ~5 kg; jugular ~2 kg; trachea ~15 kg; vertebral ~30 kg.
5. Salivary dribble from angle of mouth = antemortem hanging (vital sign, cannot be faked).
6. Amussat's sign = transverse intimal tear of carotid in hanging; Brouardel = subcutaneous ecchymosis in the groove.
7. Tardieu spots (petechiae) florid in strangulation/throttling; sparse in typical hanging (pale face).
8. Hyoid fracture commonest in throttling and in the elderly (post-ossification); superior horn of thyroid most often broken.
9. Throttling is always homicidal; hanging usually suicidal; ligature strangulation usually homicidal.
10. Judicial hanging → hangman's fracture (C2 fracture-dislocation), knot below angle of jaw.
11. Neck dissection at autopsy is done last and bloodless to avoid artefact.
12. Café coronary = bolus death mimicking MI; autoerotic asphyxia = accidental partial hanging with escape mechanism.