Ligature strangulation

Dr. Muditha VidanapathiranaMBBS, DLM, MD, MA, MFFLM (UK)

Senior Lecturer. Department of Forensic Medicine

FOMS, USJP

Definition

• Constriction of the neck by a ligature,

• Where constricting force is other than the body weight.

Traditional names

• 1. Garroting- Eg. In punishment killing or violent robbing.

• 2. Judicial execution in Spain.• 3. Catalan garrote- Spike enter the neck, causing

injuries to medulla and spinal cord.• 4. Lathi- In India.

Questions

• 1. Appearance and significance of marks on neck in ligature strangulation.

• 2. Autopsy features of ligature strangulation.• 3. Difference between low point suspension

and ligature strangulation.

Aims of investigation

• Cause of death- – have to differentiate from hanging, specially low

point suspension.

• Mechanisms of death,• Manner of death,

Circumstances1. Homicidal- LS

– Almost all cases.– Usually associated with sexual assaults eg. Rape-

murders.– So the incidence of ligature strangulation is high

among females than males.•

2. Suicidal-LS– Rare.– Can tie a ligature with at least one knot, before

loosing consciousness (ie. Within 10-15 seconds).– Some times several turns around neck with out

knots.– Some times windlass method. Put a noose with a

fixed knot around the neck, and then put a stick between the noose and the neck, which is turned several times to constrict the neck. When he looses the consciousness, the pressure will not released due to the stick, which prevents the reversing.

– Plastic locks use to tie the neck. Eg. Which comes with electrical items.

3. Accidental –LS

– Clothes used around neck with shalvars, Ties or scarf can entangle with a turning machine. Eg. Unprotected fans, wheel of a motor bike, or industrial machines.

Mechanisms of death1. Occlusion of veins and carotid arteries,2. Occlusion of air ways.3. Heart failure due to CCI (cumulative cardiac insult) - resulting in cerebral hypoxia.– Ligature obstruct both jugular veins and carotid arteries,

but cannot obstruct vertebral arteries . Therefore blood continues to perfuse to head more than draining out by small vertebral venous plexus. So the venous pressure in the head increases, resulting asphyxial signs above a tide mark in neck.

– Not like in manual strangulation, Ligature will maintain the obstruction more than 4 minutes resulting death due to occlusion of veins, arteries or airways.

– Occlusion of vessels take place more than other mechanisms.

Postmortem investigation• Authority- Magistrate order.• History-–Of the incident–After the incident.–Before the incident- past medical history-

psychiatric illness, previous suicidal attempts.• Visit to the scene- –Almost always a third person is involved. So take

photographs, collect trace evidences etc.

Autopsy• Identification –

• by relatives or friends• Preliminary investigations

• Photographs• X-rays- of neck AP and lateral,• Trace evidences- nail clippings or scrapings,

hair, fibres, swabs from oral, anal and vaginal.• Clothing examination.• External examination

External examination• General– Identification features- if an unidentified body.–Post mortem changes to asses time since death.

Eg. Cooling, rigor mortis, putrefaction. Etc.–Hypostasis – not in extremities as in hanging.

• Specific- 3 aspects.–1. Features due to mechanism of death–2. Feature due to agent – ligature and ligature

mark.–3. Features due to circumstances.

Features due to Mechanism of death

• A. Asphyxial- Vessels obstruction (jugular and carotids) and CCI are the common mechanisms. Which can cause raised venous pressure in the head resulting asphyxial sings above a tide mark in neck.

–Petechiae, –bluish discoloration, –congestion and oedema, –confluent haemorrhages.

2. Features due to agent (ligature and ligature mark)

• A. Describe the ligature-• Type- soft or hard, patented or not, broad or narrow,»Usually use a ligature available at the locality. Eg.

Brassier strap, towel, coir ropes etc.»Special techniques such as windlass etc.

• Turns- single or multiple. • Knots- single or multiple or non.

– Remove the ligature by cutting it sparing the knot for future references.

• B. Then describe the ligature mark.

• Ligature mark description,–Ligature mark depends on, type of ligature,

direction of application, force used, duration of constriction.–Some times no or minimal ligature mark, if

soft ligature (eg. Clothes) x short duration ( eg. Removed soon after death).

Ligature mark description…. • 1. Site- on or below the laryngeal cartilage.• 2. Size-

• length- right round the neck.• Width,• Depth- equal right round.

• 3. Shape-• Patented- can compare with the ligature when it is

recovered.• Initially yellow, then becomes brown with drying.• One or more turns can be present. • One or more knot marks can be present.

• 4. Defense scratches- –vertical, multiple , parallel, nail abrasion.

• 5. Differentiation from hanging-–Ligature strangulation mark usually not

mimic hanging, except strangle with ligature and then pull along the ground from the free end of the ligature resulting an inverted V appearance at the knot mark.

• 6. But hanging mark (specially complete suspension with slip knot or low level suspension) can mimic ligature strangulation. So the differentiation is done by following features of ligature strangulation.• On or below the laryngeal cartilage,• Horizontal (not raise toward the knot)• No gap under the knot. Runs right round.

(except if, hair or clothing intervene the ligature and neck)• No inverted V appearance at the knot mark.

Can have a cross over point. • Depth is equal right round the neck.

7. But some times, if very low level suspension with sliding knot can mimic ligature strangulation.

• Eg. Runs right round, with out gap or inverted V appearance under the knot, and can be found on or below the larynx with asphyxial features.hypostasis may not found in extremities in complete hanging. Deepest on the opposite side to the knot is also can be negative if a soft ligature is used.

• In such situations, has to be used other evidences such as,– i. scene finding- in masochistic practices of

accidental hanging, in suicidal or in homicidal hanging. ii. Injuries on the body due to circumstances. etc.

8. Differential diagnosis, exclusion.

• Fat freezing at neck skin creases in obese or infants after refrigeration.• Tight collar with putrefaction.• Elderly with heart failure- asphyxial

features with prominent skin creases of the neck.

• 9. Red margins on either side of the ligature.

–These are due to displacement of blood beneath the ligature but not considered as a vital reaction.

• 10. Red haemorrhages can be found on the ligature mark.

• 11. Not necessarily indicate AM ligature strangulation mark.

–Even strangled 2 hours after death, can receive same features as AM.

• 12. No other injuries usually found on neck.–If found, DDs,

–Self inflicted defence scratches,–Homicidal nail abrasions,–During resuscitation attempts.

3. Features due to circumstances• In suicidal ligature strangulation-

–May be able to put at least one knot before loosing consciousness. If multiple knots, more favor of homicidal.–Repeated encircling with or with out

knots.–Windlass method,–Elastic ligatures, eg. Tourniquet.–Plastic lock tie-.

• If accidental ligature strangulation-–Constriction by clothes around

neck when they entangled with turning machines or fans or wheels.

• If homicidal- LS–Usually with sexual assault. Genital

and hymeneal injuries, bite marks etc can present. –Evidence of struggling on the

body.eg. Abrasions, contusins, lacerations, cuts, stabs, etc.

Internal examination• Features due to Mechanism of death– Asphyxial features- petechiae, bluish discoloration,

congestion and oedema, haemorrhages on epiglottis.• Features due to agent (ligature)– Anterior compartment- sub-cutaneous tissues and muscles

have minimal haemorrhages (20% cases). Glands and common carotid artery can get injured rarely.

– Middle compartment- laryngeal fractures- depends on level of constriction-» thyroid superior horn fractures, » cricoids fractures, »hyoid fractures. Oesophagus –usually spared.

– Posterior compartment- usually spared.• Features due to circumstances-– Genital injuries and bodily injuries in sexual assault.

Lab investigations

• 1. Blood for toxicology- alcohol, drugs, poisons

• 2. Nail clippings or scrapings.• 3. Hair- if clenched in hands with cadavaric

spasms.• 4. Ligature mark – histology.