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Condition in which supply of oxygen to blood and tissues has been reduced below the normal level by some interference with respiration.

1. Disease of circulatory or respiratory system

2. Interferance with respirations

Breathing in atmosphere deficient in oxygen.
Inhalation of irrespirable gases like CO.
Poisoning with respiratory center depression like narcotics & anesthetics.
Mechanical interference with reapiration.

Signs of Asphyxia:

Cyanosis (due to stasis and congestion)
Increased capillary permeability (causing tissue edema)
Petechial hemorrhage
Persistant fluidity of blood (due to fibrinolysis)
Cardiac dilatation.


1. Internal findings:

Blood- dark in color, more fluid, coagulate slowly.
Right sided heart-distended with blood
Left- empty
Lungs- Engorged, congested, emphysematous, edematous, exudes copious frothy fluid on cut section.

2.External findings:

Face- Swollen, cyanosed, marked with petechial hemorrhage
Eyes- Open, prominent, pupils dilated, injected conjunctiva
Sub-conjunctival heamorrhage may be present
Lips, ears, finger nails- Deeply cyanosed
Neck veins- Prominent
Mouth & nostrils- Oozing
Hands- Clenched
Hypostasis- Purple in color
Semen may be voided
Urine and feces incontinence
Trachea & bronchi- Congested, contain blood stained frothy fluid
Petechial hemorrhages- can be found on lungs, heart & brain
Abdominal viscera, brain, meninges- Congested


It includes-
Smothering (obstruction to air passages from outside)
Choking (obstruction to air passages from inside)
Traumatic asphyxia (pressure on chest obstructing respiratory movements)


It is a form of asphyxia caused by mechanical occlusion of external air passage.

Post-mortem findings:

Site of distribution of lividity
Suggestive of suffocation
Bruises & abrasions over mouth & nostrils
Nasal septum may be fractured
Signs of struggle may be present

ML Aspect:

Homicidal (difficult in healthy young adults)
Commoner method for infanticide
Accidental (in children during sleep & breast feeding; may occur in alcoholics or epileptics)
Suicidal (almost impossible, extremely rare)


It is a form of asphyxia caused by mechanical occlusion within air passage by a solid object.

Post-mortem findings:
Object responsible for choking is found in respiratory passages,
Other signs of asphyxial death.

ML Aspects of Choking:

Mostly accidental-
Impaction of food, false teeth & other foreign bodies,
Inhalation of vomitus in alcoholics,
Regurgitation of food in infants,
Impaction of coin, pea, grape, or nut,
Tumors of larynx
T.B. Laryngitis
Homicidal (common for infanticide)
Suicidal (extremely rare)

Traumatic Asphyxia or Crush Asphyxia

It is a form of asphyxia, which results from prevention of respiratory movements by means of mechanical compression.

Post-mortem findings:

Well defined demarcation line between upper (discolored) and lower (normal colored) body part,
Face and neck deeply cyanosed,
Numerous petechiae found over scalp, face, neck and shoulders,
Bilateral, multiple rib fractures (usually at their angles),
Injuries to lungs and heart,
Other signs of asphyxial death.

Traumatic asphyxia due to pressure on the chest from an overturned tractor. The extensive congestion and petechial haemorrhages in the head and neck are typical of this type of asphyxia.
ML Aspects of traumatic asphyxia:

Mainly accidental-
Run over by a car
Fall of a tree
Collapse of a house
In crowds (during Haj)
Bansdola (homicidal compression of chest by means of bamboos)


It is a form of asphyxial death brought about by suspension of the body and constriction of neck by a ligature around it.
Partial hanging- when the feet touch ground
Complete hanging- when feet don’t touch ground

Causes of death in Hanging:

Cerebral congestion or congestive suboxia
Vasovagal inhibition or shock
Injury to spinal cord
Combination of the above causes.

The spiral weave of the rope can be seen in this
horizontal ligature mark caused by hanging

Suicidal hanging: the rope rises to a point, leaving a
gap in the ligature mark – the suspension point – on the neck.

Post-mortem findings:

1. Nature of ligature:

Time, the body has remained suspended
Intervention of clothes, beard, skull hair etc.

2. Position:

Above thyroid cartilage- 80%
On the thyroid cartilage- in cases of partial
Below thyroid cartilage- very rare

3. Course of direction:

Oblique & interrupted at place-usually of knot
Circular- if suspension is in front
Oblique & circular- if ligature is passed around the neck more than once.

4. Color:

Pale in early period-later on becomes yellowish & brown then dark brown or chocolate colored.

5.External appearances other than ligature mark:

Neck- stretched & elongated, bend to side opposite the knot
Face- swollen & blue
Eyes- protruded, dilated pupils, conjuctivae congested
Tongue- protruded, saliva dribbling from the corner of mouth
Head & neck- petechial hemorrhage
Nails- blue
Sometimes face become pale & eyes and tongue less protruded in case of arteries and veins are compressed together
Genitals- swollen & congested
Rigor mortis- slow and longer
PM lividity- on dependent parts e.g. extremities, breasts, penis & testicles.

6.Abrasions and bruises:
  • May be found when ligature is hard & tough.
7.Number: 1-suicidal, >1- homicidal

8.Internal appearance:
  • Spinal cord injuries
  • Transverse tear of the intima of the carotid arteries & extravasation of blood within the wall
  • Pons and medulla may be injured
  • Sternocleidomastoid and platysma may be ruptured
  • Thyroid cartilage may be fractured
  • Heart, right side full of dark blood & left empty
  • Abdominal organs congested and bladder empty
  • Hyoid bone may be fractured in above 40 age group.

Signs of antemortem hanging:

A suspension mark with signs of vital reaction e.g. hyperemia, ecchymosis, abrasions & bruises.
Ligature mark can be produced 2 hours after death but without vital reaction.

ML Aspects:

Most commonly, it is suicidal
More common in females than males
Direction of ligature mark
Circular- homicidal
Presence of poison in body suggest suicide
Signs of struggle suggest homicide.


It is a form of asphyxia caused by constricting the neck by any means other than body weight.
Constricting force being hands- in throttling; elbow- in mugging; knee, foot- bansdola; some hard object.

Causes of death in strangulation:

Vasovagal inhibition
Cerebral congestion
Combination of above factors
It is well accepted that in some cases of strangulation,and in rather more cases of hanging, the sudden application of pressure onto one or other carotid sinus can initiate rapid death, through the vagally mediated cardiac bradycardia described above, before any congestive or petechial signs have time to appear –and so the victim dies with a pale face and no petechiae.
For congestion and petechae,hypoxia of min 15-30 s is reqd

PM Findings

1. External findings
Neck findings
External findings other than neck
2. Internal findings

External findings
Neck findings
Strangulation by Ligature:
Fragments of epidermis on suspected ligature material, if found.
Usually on or below thyroid cartilage.
Encircle the neck completely
Bruising & ulceration at the site of knot

Throttling or Manual Strangulation:
Marks of fingers & thumb on either side of neck
Look like bruises soon after death
There may be bruises on mouth, nose, cheeks, forehead and lower jaw.

Strangulation by means of a Stick:
Bruises in front of the center of the neck
Similar mark will be present on nape of neck if two sticks are used.

B. External findings other than in neck

  • Signs of asphyxia.
  • Face- swollen, cyanosed & marked with petechial haemorrhages.
  • Eyes- prominent, conjunctiva injected and pupils dilated.
  • Lips- blue.
  • Bloody froth from mouth, nose & ears.
  • Tongue- swollen, bruised & bitten by teeth.
  • Hands- clenched.
  • Urine, feces and semen may be discharged.
  • There may be injuries on chest

Petechial haemorrhages on the eyelid in a case of manual strangulation.

Conjunctival haemorrhages in manual strangulation

Bruising of the neck in manual strangulation.

Homicidal strangulation with a soft silk ligature. The folding of the material has caused the deep grooved mark and the fainter red mark above it.

2. Internal findings

Extravasation of blood into subcutaneous tissue above and below the ligature mark.
Laceration of the superficial muscles of neck.
Fracture of hyoid bone, tracheal rings and cervical vertebrae.
Lungs- dark, frothy blood on section
Heart- right side full of dark blood and left empty
All abdominal organs are congested.

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