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AsphyxiaDefination.

Asphyxia commonly equated to lack of oxygen.

- etynnologically means absence of pulsation

- anything that interfers with oxygenation can be caledasphyxia though anoxia or hypoxia are more accurate.

- many medical / forensic conditionc lead to asphyxia.

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Mechanical Asphyxia

Of most forensic importance.

Normal oxygen tension 90 100 mutth2.

Post mortem analysis of no value.

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Types of asphyxia.

Suffocation death from deprivation of oxygen.

- plastic bag.

Smothering blockage of external air passages.

- overlaying infants.- gagging.

Chocking blockage of upper airway by foreign body food,foreign body dentures.

Throthing strongulation by hand.

Strangulation most specific hand or ligatures ( garroting)apply force on neck.

Mugging pressure from arm crroked from rear.

Traumatic asphyxia.

Sexual asphyxia autoerotic or masochistic practices.

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Classic signs of Asphyxia.

Petechial hemorhages Tardiens spots.

Congestion and oedema.

Cynosis.

Engorgement of the right heart.

Fluidity of blood.

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Fatal pressure on neck

Most complex and controvesial area of

asphyxial death.

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Mechanism of death

Airway occlusion.

Occlusion of neck veins.

Compression of neck veins. Compression of carotoid arteries.

Nerve effects pressure baraveceptor in carotid

sinuses, caratid sheths and carotid body can lead

to bradycardia or total cardiac arrest ( vagalinhibition, vasovagal shock, reflex cardiac arrest.

- Basis for commando punch , common in

strangulation, choking, drydrowing.

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Manual Strangulation.

Common method of homicide.

Common in domestic homicides.

Assailant often stronger than victim.

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Autopsy appearances of

manual strongulation.

Two groups (i) Local signs of violence.

(ii) Signs of mechanism of death.

(i) Bruising ( usually assailants) and

abrasions victims or assailant.

- injuries may be anywhere on neck toclamicle.

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Victims abrasions usually run parallele andvertically in the long axis ofneck.

Autopdy necessary to take fingernailscrappings for DNA.

Bruising with hematomas neck tissues.

Beware of spourious bleeding.

Larynx damaged in various ways.- radiography important.

- thyroid horns and hyoid horns usually fractured.

- cricoid and main alar of thyroid may be cracked.

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Ligature strangulation.

Usually homiscidal ( some suicidal a few

accidental).

Variety of objects used.

Mode of death more oftern classic asphyxia.

Ligature mark pattern may be imprinted inslin.- encircles neck horizontally and at lower level ( above

or below larrygeal prominence).

- often a crossover point present in homicide.

- oftn multiple in suicide.

- doesnot usually

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