Asphyxia forensic medicine and toxicology

1. ASPHYXIA
Dr. C.P.Singh

2. Asphyxia
Asphyxia (Greek, ‘pulselessness’ or ‘absence
of pulse’) is a condition caused by interference
with the exchange of oxygen and carbon dioxide
in the body.
• „
Asphyxia literally means ‘defective aeration of
blood’ due to any cause.

4. Hanging
• Hanging is a form of asphyxia caused by
suspension of the body by a ligature which
encircles the neck, the constricting force being
at least part of the weight of the body.
• „Near-hanging: Patients who survive a hanging
injury long enough to reach the hospital

5. Types Of Hanging
• On the basis of position of the knot
• „Typical hanging: When the point of
suspension is
placed centrally over the occiput, i.e. the knot is
at the nape of neck on the back.
• „Atypical hanging: Knot of ligature is anywhere
other than on the occiput.

7. • On the basis of degree of suspension
• „Complete hanging: Body is fully suspended and
no part of body touches the ground. Constricting
force is weight of the body.
• „Incomplete or partial hanging: Lower part of the
body is touching the ground (toes or feet touching
the ground) or in sitting, kneeling, lying down
or prone position. Weight of the head acts as the
constricting force.

9. Autopsy of Neck (Asphyxial Deaths)
Photograph of the victim along with ligature (if
present) is recommended.
• External Examination
• General features
• „Clothing and personal effects.
• „Distribution of lividity, rigor mortis, and algor
mortis.
• „Bleeding from any sites, discharge of semen,
urine or fecal matter

10. Ligature
Is ligature present in situ or removed?
• Knot: If in situ, note knot position, number of
loops.
• Ligature description
• „Type of material
• „Circumference of noose
• „Width
• „Nature of knot (slip-knot or fixed).

11. • Description of ligature mark or furrow
• „Course (angled or straight)
• „Width
• „Associated skin changes or trauma
• „Relation to thyroid cartilage
• „Pattern
• „Neck circumference at level of furrow (to
determine degree of neck constriction)
• „Transfer of ligature material.

13. Postmortem Findings in Hanging
External Findings
• 1. Face
• i. Swollen, cyanosed face due to impaired venous return and
accumulation of blood.
• ii. Prominent eyeballs due to increased pressure resulting from passive
accumulation of blood.
• iii. Dilated pupils: If the knot presses on cervical sympathetic, eye of
the same side may remain open and pupil is dilated (la facie
sympathet-ique).It indicates antemortem hanging.
• iv. Subconjunctival hemorrhages.
• v. Protrusion of tongue due to pressure on floor of the mouth by
ligature. It is usually swollen and blue. Injuries include bite marks with
or without underlying small hemorrhages (‘marginal’ hemorrhages).
• vi. Bleeding from nose/ears due to impaired venous return and
increase in pressure.

15. . Neck
i. Ligature mark (‘furrow’)
• Site: Usually above the hyoid bone.
• Size/shape: Depends on the type of material used.
• Direction: It runs obliquely, backwards, non-continuous,
upwards and towards the point of suspension. Mark is non
continuous because of a gap at the nape of neck, and hair
intervening between ligature material and the skin
underneath. When the knot is in contact with the skin, it is
usually inverted ‘V’ shaped, due to extension of ligature
material downward on both sides from the knot above
• Skin at the site: Usually depressed/grooved, pale in color, but
later becomes yellowish brown, dry, hard and parchment-like
with small abrasions at its edges, corresponding to the
thickness and edges of the rope. These abrasions, known as
rope burns, are due to frictional force.
The pattern of ligature may be reproduced in the furrow.

16. • Other parts of body
• i. Tardieu’s spots: May be present on forehead, over the
eyelids, under the conjunctiva and near the temple.
• ii. Cyanosis of fingernails.
• iii. Purple colored postmortem staining in the lower limbs
and lower regions of upper limbs (hands/forearms)—glove
and stocking PM staining.
• iv. Hands are usually clenched.
• v. In males, there may be penile turgidity and involuntary
discharge of semen.
• vi. In both sexes, there may be an involuntary discharge of
fecal matter and urine

17. Internal Findings
„Neck
• i. Subcutaneous tissue underneath the ligature mark is dry, white,
firm and glistening. Platysma and sternomastoid may show
hemorrhages, and are sometimes ruptured.
• ii. Hyoid bone may be fractured in persons, more commonly above
the age of 40 years. The fracture is usually due to ligature forcing
the hyoid bone backwards, which results in increased divergence of
greater horns (anteroposterior compression fracture), but it can be
a traction fracture.
• iii. Transverse carotid intimal tears may be seen in obese victims,
long drops and posteriorly placed knots (Amussat’s sign).
• iv. Vertebral artery injuries—rupture, intimal tear and subintimal
hemorrhage (most frequent) may
• be present.
• v. Larynx and trachea are congested

18. • Lungs: They are congested, distended and
emphy-sematous with plenty of Tardieu’s
spots subpleurally, particularly at the
interfaces of the lobes.
• „Brain: Congested and shows multiple
petechiae.
• „Viscera: All the abdominal organs are
congested.
• „Blood: Fluid and purplish in color.

19. • There may be hemorrhages on ventral surface of
the intervertebral disks beneath the anterior
longitudinal ligament in the lumbar spine
(Simon’s sign–a vital sign of hanging). It may also
be seen n other traumatic elongation or
overextension of spinal column (e.g. traffic
accidents), drowning and putrefaction (‘false
positive’)

20. Lynching
Lynching is a form of homicidal hanging. A
suspect, an accused or an enemy is
overpowered by several persons, acting jointly
and illegally, and hung him by means
of a rope from a tree or some similar object. It
was prevalent in North America, where it was
practiced by whites on blacks.

22. Judicial Hanging
In case of judicial hanging, the ligature is looped around
the neck with the knot under the chin (submental), but
subaural (below auricle) knot is also used.
The drop is at least the height of the person (5–7 feet,
depending on the weight) and the hanging is complete. The
ligature around the neck causes a forceful jerky impact on the
neck at the end of the fall, so as to cause fracture of cervical
column (fracture dislocation of C2 from C3, rarely C3 and C4
vertebrae—hangman fracture) with stretching or tearing
of cervical spinal cord, but not decapitation. In juidicial
hangings, odontoid process is usually not fractured

24. Hangman’s fracture
It was found that when the hangman’s knot
was placed beneath the chin, death occurred
rapidly because of fracture of the pedicles/lamina
of C2 vertebra and a traumatic spondylolisthesis of
the C2 over C3 (anterior subluxation/dislocation.
This knot placement became standard, and most
efficient method of execution. The mechanism of
the injury is forcible hyperextension of the head.
This injury may also be seen in sports, fall or road
traffic accidents.

26. Strangulation
It is a form of violent asphyxial death caused
by constriction of air passage at the neck by
means of a ligature or by any means other than
suspension of the body.

27. Classification
„Ligature strangulation: When ligature material is used to
compress the neck.
• „Manual strangulation or throttling: When human
fingers, palms or hands are used to compress the neck.
• „Mugging: Strangulation caused by holding the neck
of the victim in the bend of elbow or knee of the
assailant. It is an attack, usually from behind, and may
leave no external or internal injury mark. It is also known
as chokehold. This hold is not permitted in wrestling,
because of its danger.

30. • Bansdola: A bamboo or stick is placed across
the back of the neck and another across the
front. Both the ends are tied with a rope due
to which the victim is squeezed to death.
When a foot or knee is placed across the front
of throat and pressed while the victim is lying
on ground, same condition will follow. If a
stick or foot is used, a bruise is seen in the
center, across the trachea corresponding to
the width of the object used.

32. • Garroting: Strangulation is caused by
compression of the neck by a ligature which is
quickly tightened by twisting it with a lever
(rod, stick or ruler) known as Spanish
windlass, which results in sudden loss of
consciousness and collapse

33. • Accidental strangulation
• „Accidental strangling may occur in uterus, when
the movement of foetus causes the umbilical cord
to encircle the neck.
• „Children may get entangled in ropes during play
or strangled in their cots.
• „Persons under the influence of alcohol, epileptics
and imbeciles may be strangled either by a tight
scarf or collar or necktie.

34. • Throttling or Manual Strangulation Asphyxia produced by
compression of the neck by human hands.
• Cause of death
• i. Asphyxia from obstruction of respiration.
• ii. Cerebral anoxia from interference with cerebral
circulation.
• iii. Vagal inhibition from pressure on carotid nerve plexus
consisting of fibers of vagus, sympathetic and
glossopharyngeal nerves. About half of the
• deaths are due to vagal inhibition.
• Pressure must be applied for 2 minutes (min) or more to
cause death

36. • Suffocation It is a form of asphyxia caused by
mechanical obstruction to the passage of air
into the respiratory tract by means other than
constriction of neck or drowning.
• Classification
• i. Smothering ii. Choking
• iii. Gagging iv. Overlying
• v. Traumatic asphyxia vi. Burking

37. • Smothering It is a form of asphyxia caused by
mechanical occlusion of external air passages,
i.e. the nose and mouth by hand, cloth, plastic
bag or other material.

38. • ii. ChokingIt is a form of asphyxia caused by an
obstruction within the air-passages by a foreign
object, like coin, fruit seed, toffees, candies, fish
or any other material.
• In an epileptic attack, tongue may fall back on
to posterior pharyngeal wall causing choking.

39. • The phases of acute fatal airway obstruction
are:
• i. Penetration of the object into the airway.
• ii. Obstruction of the airway.
• iii. Failure to expel once the obstruction has
occurred

40. Café-coronary
This is a condition of accidental choking wherein
a bolus of food produces complete obstruction
of the larynx.
• „It is called so, because it mimics a heart attack
and is usually seen in an intoxicated restaurant
patron.

41. • iii. Gagging Gagging is a form of asphyxia which results
from pushing a gag (rolled up cloth or paper balls)
into the mouth, sufficiently deep to block the pharynx.
It combines the features of smothering and choking.
Initially, the airway may be patent through nose,
but collections of saliva, excessive mucus with
edema of pharynx and nasal mucosa causes complete
obstruction.

42. • v. Overlaying Overlaying or compression suffocation
• results from compression of the chest, nose and
mouth, so as to prevent breathing.
• „It is a form of accidental smothering of an infant by a
nursing mother, sharing a bed with her child who may
roll over during sleep and occlude the air passages.
„Ethanol intoxication or a medical condition can be
a factor depressing an arousal response in the older
bed-sharer.

43. Traumatic or Crush Asphyxia/Perthes Syndrome
Asphyxia resulting from respiratory arrest due to mechanical fixation of
chest, so that the normal movements of chest wall are prevented.
Causes
i. Due to house collapse, accidentally or in wars/earthquake.
ii. Stampede by crowd, running in panic, e.g. due to outbreak of fire in
a movie hall/mall/public gathering.
iii. Run over by a vehicle or overturned vehicle (especially tractors).
iv. Collapse of wall inside a mine or trenches (cave-in), in bunkers of
sand or grain.v. When held between the buffers of two bogies of a
train.vi. Restraint of suspects by hogtying practiced in some
States in the US by police

44. • Burking
„It is a combination of homicidal smothering and
traumatic as Method: A victim was invited to
their house and given alcohol. When drunk, he
was thrown on the ground. Burke would kneel
or sit on the chest and close the nose and
mouth with his hands, and Hare used to pull him
around the room by the feet till he is dead.

46. • In typical hanging, knot is placed at:
• A. Occiput B. Chin
• C. Left side of mandible D. Right side of
mandible
‘La facies sympathique’ is a condition seen in cases of:
• A. Hanging B. Strangulation
• C. Throttling D. Railway accidents
Following is most suggestive of antemortem hanging:
• A. Salivary dribbling B. Congestion of lungs
• C. Ligature marks D. Petechial hemorrhages

47. Hanging causes injury to:
• A. Carotid artery B. Esophagus
• C. Trachea D. Vertebral artery
Lynching is a type of:
• A. Homicidal hanging B. Suicidal hanging
• C. Judicial hanging D. Accidental hanging
The ‘knot’ in judicial hanging is placed at:
• A. Behind the neck B. Side of the neck
• C. Below the chin D. Choice of hangman
Hangman’s fracture is:
• A. Spondylolisthesis of C2 over C3
• B. Fracture of odontoid process
• C. Fracture of transverse process
• D. Dislocation of C5

48. Mugging is compression of neck by:
• A. Wooden sticks B. Rope
• C. Bend of elbow D. Hand
Bansdola is a form of strangulation by:
• A. Ligature B. Hands
• C. Wooden sticks D. Bend of elbow
Spanish windlass is practiced in which form of strangulation:
• A. Bansdola B. Garroting
• C. Throttling D. Mugging
Ligature mark is horizontal in:
• A. Hanging B. Strangulation
• C. Both of the above D. None of the above

49. • Fracture of hyoid bone is indicative of:
• A. Manual strangulation B. Ligature strangulation
• C. Bansdola D. Hanging
• Hyoid bone fracture does not occur in
• A. Hanging B. Strangulation
• C. Throttling D. Choking
Outward displacement of fractured hyoid bone is seen
in:
• A. Manual strangulation B. Ligature strangulation
• C. Hanging D. Bansdola

50. • A person was brought to the emergency with a history of something stuck
in his throat during his dinner which progressed to dyspnea, the probable
diagnosis
A. Myocardial infarction B. Choking
C. Pulmonary embolism D. Aortic dissection
• During autopsy, foreign body is found in respiratory tract; manner of
death is:
• A. Homicide B. Suicide
• C. Accident D. Natural
Accidental choking of respiratory passage by bolus of food:
• A. Gagging B. Overlying
• C. Cafe coronary D. Burking
• 23. Cafe coronary commonly occurs when a person is:
• A. Intoxicated B. Eating fatty food
• C. Eating meat D. Eating fish