Ligature strangulation
Dr. Muditha Vidanapathirana
MBBS, 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,
Circumstances
1. Homicidal- LS
– Almost all cases.
– Usually associated with sexual assaults eg. Rapemurders.
– 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 death
1. 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 historypsychiatric 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.