Ligature strangulation

Common ligatures

Manner of death

• Usually homicidal
• Accidental cases can occur
• Suicidal ligature strangulation is rare, but possible with a maintained mechanical arrangement

Mechanism of death

1. Asphyxia from airway compression, including elevation of tongue and larynx at pharyngeal level
2. Cerebral anoxia from compression of carotid and vertebral circulation
3. Venous obstruction, causing facial congestion and petechiae
4. Vagal inhibition
5. Rarely, fracture-dislocation of cervical vertebrae
   P. C. Dikshit Textbook of Forensic Medicine and Toxicology, p. 301.

External postmortem findings

• Ligature mark generally:
  • At the middle or lower neck
  • Transverse or nearly horizontal
  • Usually complete/circumferential
  • Well-defined and depressed
  • More prominent anteriorly and laterally
• Mark may reproduce the pattern of the ligature.
• A thin, firm ligature may produce a deep, parchment-like furrow. A soft ligature may leave a faint mark or none, especially in children or frail/incapacitated people.
• Face and neck above the ligature may be congested and cyanosed.
• Conjunctival and facial petechiae, subconjunctival hemorrhage, and protrusion of tongue may occur.
• Abrasions or nail scratches around the neck or face may indicate resistance/struggle.

Internal findings

• Hemorrhage in subcutaneous tissues and neck muscles beneath the ligature mark
• Hemorrhage in tissues around larynx and root of tongue
• Fracture of hyoid bone and thyroid cartilage may occur, but is not mandatory
• Rarely, carotid arterial injury/tear

Ligature strangulation versus hanging

Medicolegal importance

• It raises strong suspicion of homicide, particularly where there are defence injuries, signs of struggle, multiple turns of ligature, or internal neck hemorrhage.
• Preserve the ligature in situ when possible, photograph the body and knot, record the mark accurately, and examine clothing, fingernails, and the scene.
• A horizontal ligature mark alone is not conclusive. Correlation with autopsy and scene evidence is essential.

Autopsy findings in ligature strangulation

1. External findings

• Usually a well-defined, depressed groove at the middle or lower part of the neck, commonly at or below the thyroid cartilage.
• It is generally transverse or nearly horizontal, unlike the typically oblique upward mark of hanging.
• It often encircles the neck completely and is more marked in front and at the sides.
• The mark may reproduce the pattern, width, and texture of the ligature.
• Initially pale, it may later become dry, yellow-brown, hard, and parchment-like.
• Abrasion or bruising along the edges supports antemortem application, although interpretation must be cautious.

• Facial congestion and cyanosis.
• Numerous petechiae, particularly on the eyelids, face, conjunctivae, and sclerae.
• Subconjunctival hemorrhage and protruding/bulging eyes can occur.
• Tongue may be swollen, protruded, bitten, or bruised.
• Fine foam at mouth/nose and bleeding from mouth or nose may be present.
• These signs can be minimal or absent if death is rapid, for example from vagal reflex cardiac arrest.

• Scratch abrasions or nail marks on the neck, face, and around the mouth.
• Bruises, abrasions, torn clothing, or other injuries on the face, chest, limbs, and hands may indicate resistance or assault.
• Their absence does not exclude homicide, especially if the victim was intoxicated, asleep, weak, young, elderly, restrained, or rapidly incapacitated.

2. Internal examination of the neck

• Extravasation of blood in the subcutaneous tissues beneath the ligature mark.
• Hemorrhage in strap muscles, sternocleidomastoid, laryngeal tissues, and muscles at the root of the tongue.
• Bruising around the larynx and pharynx.
• Fracture of the hyoid bone and/or thyroid cartilage may occur, especially with considerable force, but their absence does not rule out ligature strangulation.
• Carotid sheath hemorrhage, intimal tear, or carotid arterial injury may rarely be seen.
• Fractures should be assessed with care because resuscitation, decomposition, and dissection artefact can complicate interpretation.

3. Internal general findings

• Congestion and edema of lungs
• Dark fluid blood and visceral congestion
• Petechial hemorrhages on serosal surfaces may occur
• Cerebral congestion/edema may be present

Medicolegal importance

1. Usually indicates homicide
   Ligature strangulation is classically regarded as predominantly homicidal because external force is needed to tighten and maintain the ligature. However, accidental and