Forensic Medicine

1. Asphyxia
Dr Nikita Prabhakaran
FM 2.20 – FM 2.23

2. • Anoxia
complete deprivation of adequate oxygen
supply at tissue level.
• Hypoxia
deprivation of adequate oxygen supply at
tissue level that resultsfrom asphyxia.
• Asphyxia (Gk a, not; sphyzein, to throb)
• Defective oxygenation of the blood (Exclusion of air from lungs)
• Literal meaning is without throbbing or pulse,
• which occurs soon after asphyxia.

3. • Types of asphyxia
1. Mechanical – eg : Hanging
2. Pathologial – eg : disease of upper or lower airway
3. Toxic/ chemical- eg: causing diaphragm paralysis
4. Environmental- eg: high altitude
5. Traumatic- eg : pneumothorax
6. Position/ postural- eg:restraint torture
7. Iatrogenic – eg : anaesthesia

4. What is mechanical asphyxia ???
• Broad term denoting an interference
• Referring to a condition where
• Any external pressure applied to neck, chest
or other areas of the body
• In such a way that
• respiration is difficult or impossible

5. Causes of mechanical asphyxia
• Hanging
• Strangulation
• Smothering
• Gagging
• Choking
• Traumatic asphyxia
• Drowning

6. Hanging
• aka Self-suspension
• Definition:
• It is that form of asphyxia
• Which is caused by suspension of body
• By a ligature which encircles the neck
• Constricting force being the weight of the
body

7. Types
(1) Depending on degree of suspension
(a) Complete hanging
- no part of the body touching the ground
(b) Partial hanging
-partially suspended
-some part of the body touches the ground
-only head and chest off the ground
(whole weight of the body is not necessary)

8. Complete
Hanging Partial
Hanging

9. • (2) Depending on the position of the knot
• (a) Typical hanging
• knot is just below the occiput
• on the central part of the back of neck
• (b) Atypical hanging
• knot is anywhere other than the occiput

10. Typical hanging Atypical hanging

11. • (3) According to manner of death
–1. Suicidal hanging
–2. Homicidal hanging
–3. accidental hanging

12. Fatal period
• Usually 3 to 5 minutes

13. Causes of death in hanging
1. Asphyxia trachea  15 kg (most common)
2. Venous congestion jugular veins 2kg
3. Cerebral anaemia carotid arteries 4 to 5kg
 vertebral artery 20 kg
4. Reflex vagal inhibition
5. Fracture or dislocation of cervical vertebra
sudden drop and long fall

14. Delayed death
• Aspiration Pneumonia
• Pulmonary edema
• Laryngeal edema
• Infarction of brain
• Hypoxic encephalopathy
• Brain absecess

15. Postmortem findings
• I. Specific finding
• II. Findings indicating ante-mortem status
• III. Non- specific findings

16. I. Specific findings
(a) External appearance
• Most characteristic finding is LIGATURE MARK
• Type : pressure abrasion around the neck
• Factors: numerous factors like
• Material
• Number of turns
• Any entangled materials
• Duration of suspension

18. Patterned abrasion

19. • Typical appearance in hanging –
• oblique
• Above thyroid cartilage
• Usually discontinuous
• Inverted V at the knot
• More prominent on the opposite side of the knot
• If Patterned identifying material
• If prolonged suspension parchment like appearance

20. • (b) Internal findings
• Neck is dissected under blood less field
• Subcutaneous tissue under the pressure
abrasion is pale and dry
• No prominent haemorrhages/ muscular
contusions underneath

22. • Amussat’s sign
• Transverse carotid intimal tears
• Long drops

23. Hyoid fracture – abduction fracture
Thyroid cartilage superior horns- can also be
fractured
• Hangman’s fracture
• Fracture dislocation of C2 from C3
• Sudden and long drop
• As in judicial hanging

25. • Histopathology
• Suspension within 2 hours of death
• Perimortem period
• Similar mark
• Confirmed by
tissue reaction in microscopy
enzyme histochemistry

26. Pseudo-ligature mark
• Skin folds on the neck
• May resemble a ligature mark
• Especially after refrigeration
• When there is coagulation of subcutaneous fat
• Conditions:
– Obese individuals,
– Infants,
– Decomposition

28. Infant neck folds

29. Simon’s sign
• Haemorrhage on the ventral surface of the IV
disc
• Beneath the anterior longitudinal ligament
• In lumbar spine
• In elongation and overextension

31. II. Signs of ante-mortem hanging
• Le-facie sympathique
• knot presses on cervical sympathetic
• eyes partly open
• pupils dilated
• Sign of ante-mortem hanging

33. • Salivary dribble mark
• Stimulation of pterygopalatine ganglion
• submandibular gland gets activated
• Increased salivary secretion
• Seen extending from the angle of mouth
• Opposite to the site of knot
• Sign of ante-mortem hanging

35. • Inflammatory change around pressure
abrasion
• Microhaemorrhages in the subcutaneous
tissue

36. III. Non- specific findings
• Face- congested , cyanosed, petechial
haemorrhages
• Tardieu’s spots face and inner aspects of
inner eyelids

37. • Glove And stocking hypostasis
• Seminal discharge++
• Urine or faecal discharge ++

38. Cardinal signs of asphyxia
1. Cyanosis
2. Congestion
3. Edema
4. Petechial haemorrhages
5. Postmortem fluidity of blood

39. • Internal findings:
• Lungs
• congested, edematous and tardieu’ spots
• Subpleural haemorrhages especially in the
interpleural surface
• All other organs congested, edematous

40. Cyanosis

41. Congestion of internal organs
Pulmonary congestion

42. Petechial hemorrhages
external and on internal organs

43. Antemortem Hanging
vs
Postmortem suspension

44. Strangulation

45. Definition
• Asphyxia caused by constriction of neck
• And
• the constriction force being an external force
and not the weight of the body

46. Types:
• (1) Ligature strangulation
• external force is ligature
around the neck
• (2) Manual strangulation / Throttling
• External force- compression by human hands

47. • (3) Garroting
• (4) Mugging

48. • (5) Bansdola

49. Ligature strangulation
• Compression by a ligature tied around the
neck
• Constricting force being an external force
applied

50. Postmortem appearance
(a) External
• Ligature mark
middle / below thyroid cartilage
 completely encircles the neck transversely
Bruising around
Wide area of bruising – bruising

52. • (b) Internal findings
• Neck dissection- internal layers shows bruising/
haemorrhages
• Hyoid bone fractures
• Thyroid cartilage fractures

53. Hanging Ligature strangulation
Ligature mark Oblique, discontinuity
Above thyroid cartilage, pale looking
Horizontal, continuous,
below TC, bruising around
and inside
Subcutaneous
tissue
Pale Ecchymosis under the mark
Hyoid bone Fracture++ --
Thyroid cartilage Fracture less common More common
Emphysematous
changes in lungs
----- ++++
Carotid arteries Damage +

54. Manual strangulation/ throttling
• Compression of the neck caused by human
hands

55. Typical External findings
• Six penny bruises
• Oval/ round (1.5 to 2cm wide) contusions
• Present on the neck
• due to compression from pulp of fingers
• Helps in identifying the position of the victim
and assailant

57. Finger nail abrasions
• Crescentic abrasions
• Regularly curved comma like abrasions
• If nails skid parallel linear lines of abrasions

59. • Along with all other findings of violent
asphyxia

60. Hyoid bone fractures
• Classification:
• (1) Inward compression fracture
• (2) Antero-posterior compression fracture
• (3) Avulsion fractures

62. Inward compression fractures
• Seen in throttling
• Fingers of the grasping hands squeeze
• the greater horns towards each other
• Periosteum on the outside gets fractured
• Fragment is displaced inwards
• Called as adduction fracture

64. Antero-posterior compression fracture
• Seen in cases of hanging
• Hyoid bone is forced directly backwards
• Greater horns hit against the vertebrae and
gets diverged
• Inner periosteum breaks
• Fragment displaced outwards
• Called as abduction fracture

65. Avulsion Fracture
• Violent lateral or downward movements of
thyroid cartilage
• Or there is traction in thyro-hyoid ligaments
• Causes are miscellaneous

66. Palmar Strangulation
Palm of one hand
placed horizontally over
the mouth and nostrils
Reinforced by keeping
another palm on the top
of it at right angles
Heel of the upper palm on
the front of neck
Findings similar

67. Bansdola
• One bamboo stick kept on the back of neck
• Another one on the front
Ends are tied to cause compression
Sometimes, one bamboo stick is placed on the
front and at the back- pressure applied using a
foot

69. Garroting
• Victim is attacked from behind without
warning
• Either by throwing a ligature and tying it and
twisting it with a lever or rod
• Mode of judicial execution in Spain
• “ Spanish windlass technique”

71. Mugging
• Strangulation is caused by holding the neck of
the victim in the bend of the elbow
• Attack usually from behind

72. Suffocation
• It is a general term used to indicate that form
of asphyxia where entry of air to the lungs is
prevented by any means other than pressure
on the neck or drowning.

73. Modes
• Smothering
• Gagging

74. • Overlaying
• Choking
• Traumatic asphyxia

75. (1)Smothering
• Form of asphyxia caused by closing the
external respiratory orifices either by hand
• Or
• by other means, or blocking up the cavities of
nose and mouth by introduction of a foreign
substance

78. Postmortem appearance
• Circum-oral pallor
• Pallor around nose
• Pressed against pillow– findings can be
obsolete
• Petechiae and congestion are seen in persons
who threw a struggle before death

79. • Pillow  blood. Saliva and epithelial cells
• If hands used scratches from nails
• Lips and gums show bruising and laceration
• Frenulum tears
• Face intensely congested
• Toungue may be bitten

82. • Internal findings:
• All that of asphyxia ++
• Blood stained frothy fluid  airpassages
• Mucus back of mouth
• Emphysematous changes in lungs

83. (2) Gagging
• Asphyxia resulting from forcing a cloth/ other
material into the mouth sufficiently deep to
block the pharynx
• Initially through nose airway is patent, once
saliva and mucus comes and blocks
complete asphyxia

85. Autopsy findings
• Congestion of face, petechiae on the face
• Injuries to nose and mouth may be present
• Blood may seep into back of throat
• Gag may be found soaked and hardened
• Profuse mucus
• All asphyxial findings

86. (3) Overlaying
• Results due to compression of chest so a sto
prevent breathing
• Usually happens with mother and infant on bed
• Smothering findings like flattening of face and
mouth may be present
• Blood stained froth++++

88. (4) Choking
• Form of asphyxia caused by an obstruction within
the airpassages
• Usually between pharynx and bifurcation of
trachea.
• Usually seen as accidental
• Treated by Heimlich’s maneuver

89. PM appearance
• Asphyxial changes profound in cases of
prolonged struggle
• Foreign body found wrapped in blood stained
mucoid
• Mucus in airpassages

91. Café coronary
• Healthy but grossly intoxicated person
• Who begins a meal,
• Suddenly turns blue, coughs violently, then
collapses
• Appears to be a heart attack

92. • Mechanism:
• Decreased gag reflex poorly chewed food
bolus is seen obstructing the airpassages
• PM Appearance:
• Foreign body seen occluding airpassages
• Similar to choking

93. (5)Traumatic Asphyxia
• Results from respiratory arrest
• Due to mechanical fixation of the chest
• By an unyielding substance or object
• Chest movements are prevented

94. Causes
• Crushed in a mob on the floor
• Crushing by falls of earth or stone
• Building collpases

95. Postmortem appearances
• Intense congestion, petechial and confluent
haemorrhages on the head, neck and upper chest
•  above the level of compression
• Areas of pallor seen at the levels of compression
Asphyxial findings++

97. Burking
• A method of homicidal smothering and
traumatic asphyxia
• Derived from the story of William Burke

98. • William Burke and William Hare were friends
• Use to have body supply for medical schools
• Inorder to keep up with it they use to kill
people
• Invited people were offered alcohol

99. • After throwing their victim to the ground
• Burke used to sit on them and close their nose
and mouth
• Hare used to drag the body through the room

101. Postural or positional asphyxia
• When the victim is in a certain position
• Breathing is impaired
• Eg: upside down hanging torture
• In addition venous return venous return to
the heart may be impaired.

102. DROWNING

103. Definition
• It is a form of asphyxia due to aspiration of
fluid into air-passages
• Caused by submersion in water or other fluid.
• Complete submersion is not necessary

104. TYPES
1. Wet drowning
2. Dry drowning
3. Near drowning/ Secondary drowning
4. Immersion syndrome

105. Wet drowning
• Typical drowning/primary drowning
• Water is inhaled into lungs
Death occurs within minutes due to cardiac
arrest/ fibrillation

106. Dry Drowning
• Here, water does not enter the lungs
• Death happens due to sustained laryngeal
spasm
• Due to inrush of water into the nasopharynx
or larynx

107. Secondary drowning
• Near drowning
• Refers to a submersion victim who is resuscitated
and survives for 24 hours
• Hypoxemia brain damge
• Electrolyte disturbances
• Pulmonary edema
• Cardiac arrhythmias
• Death may occur due to complications

108. Immersion syndrome
• Hydrocution/ submersion inhibition
• Death results from cardiac arrest due to vagal
inhibition
• As a result of
• (a)cold water stimulating the nerve endings on
the surface
• (b) water striking epigastrium

109. • (c)cold water entering the ear drums, nasal
passages and the pharynx and larynx

110. Mechanism of Asphyxia
• Basic deprivation of oxygen caused by
obstruction of alveolar spaces is a factor in all
types of drowning

111. Fresh water drowning
• Water
enters into
the blood
stream
• HAEMO-
DILUTION
Hemolysis
 K+
comes out
of the
cell
HyperK+
&
HyperNa+
Cardiac
arrhyth
mias –
Ventricular
tachycardia
and
fibrillation
(1) Blood concn < waterconcn

112. • (2) water denatures the pulmonary
surfactant hence even after resuscitation
alveolar collapse happens

113. Sea water / salt water drowning
• Blood conc < water conc
• Water is drawn from blood into lungs
• Severe pulmonary edema is caused
• Hemoconcentration
•  salts from lungs pass into bloodstream
•  Na+ increases
•  Bradycardia

114. Causes of death in drowning
• 1. Asphyxia
• 2. Ventricular fibrillation~ 3 to 5 mins
• 3. Laryngeal spasm
• 4. Vagal inhibition- icy cold water
• 5. Exhaustion
• 6. Injuries head striking forcibly against
some solid object

115. Postmortem appearance
• External:
• Postmortem lividity light pink in colour
• Froth  fine lathery persistent tenacious froth
at nostrils

116. • Cutis anserina / goose skin
• Puckered appearance
• Spasm of erector pilae muscles due to cold
water
• Hair is upright

117. Cadaveric spasm
• Weeds, gravel and other foreign bodies firmly
grasped in hands
• Sign of ante-mortem
drowning

118. Washer womans hands
• Soddening of the skin occurs due to
• Water entering the outer layers of skin

119. Signs of submersion
• Wrinkling  shortly after submersion
• Bleaching of epidermis 4 to 8 hours
• Soddening fingertips in 2 to 4 hours
Spreads upwards in about 24 hours
Skin becomes soddened, thickened and wrinkled
in 20 hours

121. Internal findings
• Foreign bodies in air passages
• antemortem sign
• (till the least dissectable portion)
• Or atleast after tracheal bifurcation

122. Lungs
• Become volumionous
• Doughy
• Crepitant
• Ballooned out
Congestion, edema and haemorrhages+++

123. • Drowning fluid penetrates alveolar walls 
enters tissues and blood vessels
• Emphysema aquosum
• 80 % cases
• Presumptive evidence of death from drowning

124. • If the victim is unconscious at the time of
death, no froth occurs but mere flooding
• Knows Oedema aquosum

125. • Alveolar walls may rupture due to increased
pressure during forced expiration
• Blood vessels rupture hamorrhages
• Subpleural haemorrhages  Paltauf’s
Haemorrhages

127. Fresh water drowning Sea water drowning
Ballooned out but light Ballooned out and heavy
Pale pink Purplish
emphysematous Soft and jelly like
Shape retained after removal
from body
Not retained flattens up
Sectioning- crepitus is heard Copious fluid oozes

128. Hydrostatic lung
• When a dead body is thrown into water
• Water can seep into the lung due to hydrostatic
pressure
• Resembles a drowning lung
• A drowning lung with a froth fluid on sectioning
 diagnostic of drowning

129. Diatoms
• Unicellular microscopic alagae found in water
• Complex structure of cell walls
• Contain silica, chlorophyll and diatomin
• Corroborative evidence in Ante-mortem
drowning

131. Demonstration
• Bone marrow is directly digested by nitric and
sulfuric acid
• Water squeezed out from lungs  centrifuged
and sedimented
• Observed under microscope

134. Definite signs of ante-mortem drowning
1. Cadaveric spasm
2. Foreign bodies in air passages
3. Lungs- typical appearance
4. Positive diatom test

135. THANK YOU