asphixa
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ASPHYXIA
Definition
It is any condition that leads to: - reduction of the oxygen supply to
the blood and the tissues below the the normal physiological level (hypoxia).
- elevation of CO2 in the blood (hypercapnia).
**Hypoxia means (low oxygen) while anoxia means (without oxygen).
Types of anoxia:
(1 )Anoxic anoxia:
(2 )Anemic anoxia:
-(3 )Stagnant anoxia.
(4 )Histotoxic anoxia.
Stages of mechanical anoxia or violent asphyxia:
Three stages: (1) Stage of forced respiration:
- It is due to stimulation of the respiratory center.
- Clinical picture: DYSPNEA (2) Stage of convulsions:
- It is due to cerebral irritation.
- Clinical picture: CONVULSIONS, CYANOSIS, HYPERTENSION, LOSS OF CONSCIOUSNESS, CONSTRICTED PUPILS.
(3) Stage of paralysis:
- Clinical picture: LOSS OF CONSCIOUSNESS, FLACCID MUSCLES & LOST REFLEXES, DEEP CYANOSIS, DILATED PUPILS, IRREGULAR BREATHING (Cheyne-Stokes respiration).
**Death occurs in about 5 minutes..
General signs
- Deep cyanosis. - Proptosis of the eye balls. - froth from the nose and mouth.- Dark violet or blue extensive
hypostasis.
BLOOD =fluidity increased due to (fibrinolysin _ co2 _ ca+2 ,p change )
Spots (tardieu spots ,silver spots ) All organ congested
N.B: Blood is dark and fluid in consistancy due to increased CO2 and fibrinolysis respectively.
Internal signs
Drowning
Definition: It is the mechanical anoxic death due to
submersion of the respiratory openings under water.
Causes of death: - Direct causes: mechanical anoxia
- Indirect causes:
. Reflex cardiac inhibition due to vagal stimulation
. Head injury or other fatal injuries.
Posrmortem picture of drowning
- Sure external signs:
. Froth
. Cadaveric spasm - Probable external signs:
. Related to anoxic anoxia: cyanosis
. Related to presence of the body in water:
skin is pale&wet
Goose skin
Washerwoman skin
Postmortem injuries
. Affection of postmortem changes due to presence in water:
Cooling, hypostasis, adipocere, putrefaction
**Homicidal, suicidal or accidental
ASPHYXIAL CONDITIONS-DEFINITIONS
Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid.
Hanging
Definition: It is the mechanical anoxic death due to
suspension of the body from the neck by a ligature.
Causes of death: - Cerebral ischemia. - Vagal cardiac inhibition. - Mechanical anoxia. - Transection of the spinal cord (judicial
hanging).
Post-mortem picture:
(1) General (2) Special features - Protrusion of the tongue. - Dribbling of saliva. - Hypostasis of the lower half of the body. - Neck signs: .Elongated and the head is tilted to the opposite
side of suspension point. .Ligature marks (HIGH UP in the neck, OBLIQUE,
INCOMPLETE, has an IMPRINT of the ligature).
** Homicidal, suicidal or accidental
Types of hangingPoint of comparison COMPLETE HANGING INCOMPLETE
HANGING
Other name High point hanging Low point hanging
Touching the ground Negative Positive
Circumstances Presence of a near-by table or chair
Negative
Main cause of death Cerebral ischemia Asphyxia
Face Less congested, sometimes pale
Markedly congested
Hypostasis Lower half of the body According to the part touching the ground
Type of knot Fixed knot or running noose
Always running noose
Rope marks -Incomplete with fixed knot-Above thyroid cartilage-Oblique-Deep and fades gradually towards suspension point
-Complete-Below thyroid cartilage-Transverse-Deep all through
Dribbling of saliva Positive Negative
Tear in carotid intima Positive Negative
Hyoid bone If fractured: outwards If fractured: inwards
Strangulation
Definition: It is the mechanical anoxic death caused
by constriction of the neck by a ligature occluding the air passages from outside.
Causes of death: - Mechanical anoxia. - Reflex cardiac inhibition. - Delayed edema of the glottis and
choking.
Postmortem picture of strangulation:
(1) General (2) Special features All are neck signs:
- Ligature marks:
. Low in the neck below the thyroid cartilage.
. Transverse.
. Complete.
. Deep all through.
. Abrasions and contusions taking the shape of the ligating material.
- Inward fracture of the hyoid bone and the thyroid cartilage may be fractured.
- Contusions and lacerations of the neck muscles.
**Homicidal, suicidal or accidental
Throttling «Manual strangulation»
Definition: It is the mechanical anoxic death caused
by constriction of the neck by the hand occluding the air passages from outside.
Causes of death: - Mechanical anoxia.
- Reflex cardiac inhibition.
- Cerebral anoxia.
- Delayed glottic edema and choking.
Postmortem picture:
(1) General (2) Special features All are neck signs
- Multiple contusions and fingernail abrasions.
- Inward fracture of the hyoid bone (it is the most common cause of hyoid bone fracture) and fracture of the thyroid cartilage.
- Contusions of the deep tissues of the neck.
** Homicidal, suicidal or accidental
Smothering
Definition: It is the mechanical anoxic death caused by occlusion of
the external respiratory openings by the hand or soft objects.
Causes of death: Mechanical anoxia
Postmortem picture of smothering: (1) General
(2) Special features - Multiple contusions and fingernail abrasions.
- Contusions in the buccal mucosa.
- Ventral hypostasis in cot death.
** Homicidal, suicidal or accidental
Overlaying results from compression of the chest, nose and mouth, so as to prevent breathing.
Traumatic asphyxia: Overlaying
Definition: It is the mechanical anoxic death
due to mechanical pressure by a heavy object on the chest with or without abdominal compression leading to prevention of respiratory movements.
Causes of death: - Mechanical anoxia. - Injury to vital organs.
Postmortem picture
(1) General (2) Special features - Contusions and abrasions of the chest and
abdomen.
- Fracture ribs.
- Rupture of internal organs.
- Line of demarcation between the discolored upper part of the body and the lower part.
** Homicidal, suicidal or accidental
Burking is a combination of homicidal smothering and traumatic asphyxia.
Choking
Definition: It is the mechanical anoxic death caused by
occlusion of the respiratory passages from inside.
Causes of death: - Reflex cardiac inhibition
- Mechanical anoxia
Types: - Pathological
- Non-pathological
**Homicidal, suicidal or accidental
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