2. Asphyxia
• A condition caused by interference with
respiration, or due to lack of oxygen in the
inspired air organs & tissues are deprived
of oxygen with CO2 accumulation causing
unconsciousness or death
3. Types of Asphyxia
1. Mechanical asphyxia – mechanical blockage of
air passage
– Smothering, hanging, strangulation, chocking,
drowning, external compression – blocking
respiratory movements
2. Environmental asphyxia – insufficiency of oxygen
in inspired air
sewer gases, high altitude
3. Pathological asphyxia– entry of oxygen is
prevented by disease
Laryngeal spasm, respiratory muscle weakness
4. Types of asphyxia
4. Toxic asphyxia – poisonous substances prevent
use of oxygen
CO, opium, barbiturates
5. Traumatic asphyxia
Injury to chest – pneumothorax
Long bone fracture - pulmonary embolism, fat
embolism
6. Postural asphyxia – alcohol, stupefying agents
– Trunk of body at lower level than rest of the body
7. Iatrogenic asphyxia – anaesthesia
15. Mechanical asphyxia
Mechanical blockage of air passage:
Hanging,
Strangulation,
Smothering,
Chocking,
Drowning,
External compression – blocking respiratory
movements
16. Hanging
• It is a type of mechanical asphyxia where a
• body is suspended by a ligature around the
neck and
• the force of constriction being
• the weight of the body
17. Types of Hanging
• Based on the position of the knot:
1. Typical – Knot at the nape of neck
2. Atypical – Knot anywhere except the nape of
neck
18. Types of Hanging
• Based on the position
of body:
1. Complete – whole
body is suspended
2. Partial – part of the
body touches the
ground
22. Causes of death due to hanging
1. Occlusion of airway (trachea) – 15 kg
2. Occlusion of jugular veins – 3.5 to 5 kg
3. Occlusion of carotid arteries – 3.5 to 5 kg
4. Vaso vagal inhibition
5. Occlusion of vertebral arteries – 16 kg
6. Injury to spinal cord – long drop
23. External autopsy findings
• Ligature mark on neck
• Stretching and elongation of neck
• Salivary dribble mark
• Swollen face with protrusion of tongue and eyeballs
• Bluish discoloration on lip, tip of tongue, nails
• Sub conjunctival hemorrhage
• Bleeding from nose and ears
• Dilated pupil – Le-Facie sympathique -– ipsilateral
eye opened and pupil dilated
• Glove and stocking type of Lividity
24. Ligature mark
• Depends on nature and position of ligature
material, and the time of suspension
• Situation: above thyroid cartilage, between
larynx & chin
• Obliquely placed forming inverted “V” near
the knot