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Forensic Medicine &

Toxicology Unit

Faculty of medicine

King Saud University

Violent Asphyxia Deaths

1- Hanging

Definition:

It is Asphyxial death caused by suspension of the body by a ligature around the neck,

the constricting force being the weight of the body.

Classification (types) of hanging:

A) It may be either complete or partial:

Complete: the feet are not touching the ground.

Partial: the feet are touching the ground.

B) It may be either typical or atypical:

Typical:the ligature is above the thyroid cartilage and runs symmetrically upwards on

both sides of the neck to the occipital region.

Atypical: any other position of the ligature.

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Mechanism of death:

1. Cerebral anoxia: is due to bilateral occlusion of the carotid arteries.It is the most common cause.

2- Cerebral congestion: is due to occlusion of the neck veins.

3- Asphyxia: is due to direct compression of the air passages or lifting of the larynx

to be closed by the root of the tongue.

4- Reflex vagal inhibition: is due to stimulation of baroreceptors situated in the

carotid sinuses and the carotid body

When death occurs as a result of vagal inhibition (reflex cardiac arrest),

Asphyxial signs will be absent. If death results from a cause other than vagal

inhibition, Asphyxial features (already described) will be present. However, in any

case, the following signs are also seen:

Externally:

The neck is stretched. The face is pale (veins and arteries are occluded) or bluish and

congested (only the veins are occluded). The rest of the body is cyanosed. Saliva

may be seen dripping from the mouth (It is a vital sign and is present only in hanging

but not in postmortem suspension).

Ligature mark:

Shape:

It is a depression at the site of the ligature. In the bed of the depression abrasions,

contusions and fibers from the ligature may be found.

Situation:

Above the level of the thyroid cartilage.

Asymmetrical (being deepest opposite the point of suspension).

Oblique, sloping upwards and incomplete (if fixed noose).

Transverse and complete (if running noose).

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The pattern of the ligature:

May be imprinted on the neck as a pressure abrasion.

Internally:

Fracture of the hyoid bone (outward fracture).

Petechial hemorrhage and ecchymosis of the subcutaneous tissue under the

ligature, but never in postmortem suspension.

Medico-legal aspects:

Is it hanging or postmortem suspension?

Marks of dribbled saliva.

Absence of other cause of death.

Is it suicidal, homicidal, or accidental hanging?

Suicidal: (most common):

Circumstantial evidence (history of failure).

Absence of signs of struggle.

Presence of signs of previous suicidal attempts.

Homicidal: (very rare):

Circumstantial evidence (history of threat).

Presence of signs of struggle.

Evidence of poisoning by drink or drugs, or the victim is weak.

Accidental: (rare):

Children playing with ropes. falling and hanged by ropes.

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2- Ligature strangulation

A violent Asphyxial death caused by constricting the neck by a ligature.

Mechanism of death:o Asphyxia: from compression of air passages.o Cerebral congestion or apoplexy:o Reflex vagal inhibitiono Cerebral anoxia:o Combination of any of the above:

Autopsy appearances:

On postmortem examination Asphyxial features (previously described) will

only be evident in cases where death was due to any cause other than reflex vagal

inhibition. Asphyxial features are usually absent when death results from reflex vagal

inhibition. However, in any case the following signs are also seen:

Externally:

The face is either pale or bluish and congested. The rest of the body is cyanosed.

The tongue may be protruded, swollen and bitten.

Bleeding from ears and nose may be seen.

Ligature mark:

Shape: as in hanging.

Situation:

At the level of thyroid cartilage or below.

Symmetrical (the force is equal all around the neck).

Transverse and complete (this is the usual).

May be oblique (if the victim has been dragged by the ligature).

Internally:

Neck muscles may be injured.

Fracture of thyroid cartilage may occur.

Fracture of hyoid bone

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There are Petechial hemorrhages and ecchymosis of the subcutaneous tissue

under the ligature.

Medico legal aspects:

Whether death was due to strangulation:

A postmortem swelling of the neck associated with exaggeration of skin folds

or any ornament worn around the neck may produce depressed marks. All these look

like ligature mark.

Neck dissection can differentiate between neck marks of the previous cases and

those produced as a result of ligature strangulation, where in the latter condition there

is ante mortem evidence of violence in the underlying tissues.

Suicide, homicide, or accident:

Suicide: (not common):

Circumstantial evidence.

Absence of signs of struggle.

Presence of signs of previous suicidal attempts.

The ligature is found in situ and there may be a piece of stick (used to

tighten the ligature).

Accident: (rare):

Newborns strangled by the umbilical cord.

Children plying with ropes.

Adults strangled by the neck tie caught in moving machinery.

Homicide: (common):

Circumstantial evidence.

Presence of signs of struggle.

The knot is tied on the back of the neck.

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Methods commonly used for homicidal strangulation:

Mugging: by compressing the victim's neck against the forearm.

Garroting: by attacking the victim from behind and grasping his throat or throwing

a ligature over the neck and tightening it quickly.

Bansdola: by compressing the neck between 2 sticks

Throttling: by compressing the victim's neck by the hand.

Differences between hanging and strangulation:

Circumstantial rope marks signs of resistance

3- Manual strangulation (Throttling)Violent asphyxia caused by constricting the neck by the hand.

Mechanism of death:

As in ligature strangulation.

Autopsy appearances:

When death occurs as a result of vagal inhibition, Asphyxial signs will be

absent. But, if death results from a cause other than vagal inhibition, Asphyxial

features will be present. However, in any case, the following signs are also seen:

Externally:

As in ligature strangulation.

Injuries on the neck:

Abrasions (caused by finger nails).

Contusions (caused by finger pads).

Both are found on the front and sides of the neck.

If one hand is used: 4 are found on one side of the neck and 1 on the other side. If

both hands are used: multiple are found on both sides of the neck.

The distribution is more often irregular due to repeated attempts at grasping the

neck while the victim is struggling.

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Internally:

As in ligature strangulation, but fracture of hyoid bone is more common

Whether death was due to throttling:

Evidence of violent compression of the neck during life is obtained from:

Externally:

Swelling and congestion of the face.

Abrasions and contusions on the front and sides of the neck.

Internally:

Injuries to the vessels and muscles of the neck and fracture of larynx, hyoid

and tracheal rings.

Suicide, homicide, or accident:

o Suicide: A case was recorded and it was due to cadaveric spasm.o Homicide: (most common)

- Circumstantial evidence.

- Presence of signs of struggle.

- Evidence of drink or drugs, or the victim is young or weak.

o Accident: (rare)They are due to vagal inhibition following sudden compression of the throat.

(A man killed his wife when he laid his hand on her neck).

4- Smothering:

A violent asphyxia caused by mechanical occlusion of the air passages from outside

(i.e. the mouth and nostril) by hand or by any object.

PM picture

o Asphyxial signs will be present except in case of plastic bag suffocation.o Abrasions and contusions on the skin of the face around mouth and nose(Absent if a soft material, such as a pillow, is used).

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o Contusions and sometimes lacerations on the inner aspects of lips and cheeks.Contusions of the gums and broken teeth.

Suicidal, homicidal, or accidental:

Suicide

- By hand is impossible.

- By other means (e.g. tying a plastic bag over the head) is very rare.

Homicide:

Circumstantial evidence.

Presence of signs of struggle.

Evidence of drink or drug, or the victim is young or weak.

Accident: (most common)

In infants born with membranes covering nose and mouth.

In children playing with plastic bags.

An alcoholic adult who rolls over (during sleep) and his face in the pillow.

5- Choking

Violent asphyxia caused by mechanical occlusion of the air passage from inside.

Mechanism of death:

Asphyxia: due to either complete occlusion of air passage, or partial occlusion that is

completed by spasm, edema and mucus secretion.

Reflex vagal inhibition: due to stimulation of laryngeal nerve endings.

Pulmonary infection: due to contaminated foreign body.

Autopsy appearances:

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Asphyxial signs will be present except if death is due to reflex vagal inhibition

as in the so called Caf coronary

The obstructing foreign material may be found in the respiratory passage.

In epilepsy, death may result from occlusion of air passages by the tongue, which on

examination, is found bruised and bitten at the tip and sides.

Suicidal, homicidal, or accidental:

Suicidal: (very rare).The victims are usually prisoners

Homicidal: (rare). The victims are usually infants.

Accidental: (most common) .May arise from:

Inhalation of irritant fumes.

Impaction of foreign material, such as food or denture.

Inhalation of dust and sand in falling of houses.

Inhalation of vomit or blood during operations.

Falling back of the tongue during an epileptic fit.

Caf coronary: in which a bolus of food obstructs the larynx and

stimulate its nerve endings, leading to reflex cardiac arrest (coronary attack)

6- Traumatic asphyxia (Crush asphyxia)

A violent asphyxia resulting from trauma to the chest or pressure on the

chest and abdomen which prevent respiratory movements.

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Causes of traumatic asphyxia:

Trauma to the chest which may be:

*Penetrating trauma e.g. stab injury pneumothorax lung collapse.

*Non-penetrating trauma e.g. run-over car accident fracture of ribs restriction of respiratory movements from the severe pain occurringduring respiration.

Pressure on the chest and abdomen due to:Burial in earth following house collapse.

Crushing by a crowd, as in case of a fire.

7- Drowning (Immersion):

It is a form of violent asphyxia in which death results from submersion of

mouth and nostrils of a living person under water.

Classification (types) of drowning:

1- Typical (wet) drowning: due to obstruction of air passages and

lungs by the inhaled water.

2- Dry drowning.

3- Secondary drowning (Near-drowning).

Physiopathological changes:

In fresh water hypervolemia hypoxia and potassium excess.

In salt waterpulmonary edemahypovolemia and circulatory shock.

Dry drowning:

Water in the larynx laryngeal spasm asphyxia.

Near-drowning (secondary drowning syndrome):

Pulmonary infection (contaminated water) and heart failure (from

exhaustion) may end in pulmonary edema (after the victim is rescued).

Heart failure may occur due to severe exhaustion (during the struggle to

float).

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Postmortem picture of drowning:

These are signs of asphyxia unless death occurred from shock,

syncope, or concussion.

External appearances:

Signs of immersion:

These are found in any body found dead in water (whatever the

cause of death), so they are not sure signs of drowning.

1- Coolness of the body.

2-Goose-skin the skin appears granular and wrinkled.

3- Washerwoman-skin: the skin appears wrinkled and sodden.

4-Peeling of the epidermis in the form of gloves and stockings.

5-Hypostasis is confined to the head, neck and front of the chest.

Sure external signs:

A-Froth: fine, odorless, white, or rarely blood-stained, abundant

and increases in amount with compression of the chest.

B-Cadaveric spasm of the hands on weeds, mud, sand, etc.

Internal appearances

Changes in the respiratory tract:

Voluminous lungs with indentation marks of ribs on their lateral surfaces.

Respiratory passages contain froth (having the same characters of that found

externally at the mouth and nostrils), and also foreign material (e.g. weeds, mud,

sand, etc.).

N.B.: The lungs afford the best evidence of drowning.

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Diatoms:

These are microscopic, unicellular algae, found in fresh as well as salt water. When

a live person is drowned in water, they penetrate his alveolar membrane and pass

with the circulation to distant organs.

But when a dead body is thrown into water, the absence of beating heart prevents

circulation of diatoms to distant organs.

The medico-legal (ML) importance of diatoms:

1- Sure signs of drowning,

2- Could still be identified in putrefied bodies,

3- Could give an evidence of the site of drowning (fresh or salt water species).

How to know that death was due to drowning:2. Froth at mouth and nostrils: fine, white, abundant.3. Cadaveric spasm on weeds, mud or sand.4. Lungs: voluminous, edematous with indentation marks of the ribs.5. Froth in the air passages.6. Diatoms in the tissues.

In putrefied bodies:Only diatoms could be identified