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asphyxia (Traumatic asphyxia: Overlaying (mechanical anoxic death due to…
asphyxia
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Manual strangulation
- mechanical anoxic death caused by compression of the neck by the hand or hands occluding the airways from outside.
- Causes of death:
-Mechanical anoxia.
-Reflex cardiac inhibition.
-Delayed glottic edema.
- Postmortem picture:
(1) General – Multiple contusions and fingernail abrasions on the neck
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
Cyanosis, intense hypostasis, petechial hemorrhages
Always homicidal, never suicidal or accidental
Smothering
- mechanical anoxic death caused by occlusion of the
external respiratory openings by the hand or soft objects.
- Causes of death: Mechanical anoxia
- Postmortem picture:
(1) General – Cyanosis, petechial hemorrhages
(2) Special features
-Multiple contusions and fingernail abrasions.
-Contusions in the buccal mucosa.
-Possible presence of fabric in the mouth.
- ** Homicidal, rarely suicidal or accidental
Hanging
- post-mortem picture:
(1) Ligature mark on the neck
HIGH UP in the neck, OBLIQUE, INCOMPLETE, might
have an IMPRINT of the ligature
(2) Other possible features:
Protrusion of the tongue
Hypostasis of the lower half of the body
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Ligature Strangulation
mechanical asphyxial death caused by constriction of the neck by a ligature occluding the air passages from outside.
- Causes of death:
Mechanical anoxia (occlusion of vessels and airways)
**Reflex cardiac inhibition
Delayed edema of the glottis
- Postmortem picture:
(1) General
Ligature mark: transvers, complete, deep all through Cyanosis, intense hypostasis, petechial hemorrhages
(2) Special features
**Abrasions and contusions in the shape of the ligating
material on the neck skin**
hyoid bone and the thyroid cartilage may be fractured
Contusions and lacerations of the neck muscles
Most often homicidal, Rarely suicidal or accidental
Drowning
- mechanical anoxic death due to submersion of the respiratory openings under water or other liquids
- Causes of death:
Direct causes: mechanical anoxia - typical drowning
Indirect causes - atypical drowning:
-Reflex cardiac inhibition due to vagal stimulation
-Head injury or other fatal injuries.
- Postmortem picture:
External signs: Froth from mouth and nostrils
Probable external signs:
-Related to presence of the body in water:
Skin and hair may be wet
Washerwoman skin
Postmortem injuries related i.e. to boat propeller
Affection of postmortem changes due to presence in water: Cooling, hypostasis, adipocere, putrefaction
-Related to anoxic anoxia: cyanosis
Internally – distention of the lungs so called „water emphysema” – to be confirmed in histological study - Gomori staining
Mostly accidental but possible suicidal or homicidal
Choking
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- Causes of death:
Reflex cardiac inhibition
Mechanical anoxia
- Types:
Pathological – disease (laryngocele)
Traumatic – foreign material
**Most often accidental
any condition that leads to:
-reduction of the oxygen supply to the blood and the tissues below the normal physiological level (hypoxia).
-elevation of CO2 in the blood (hypercapnia).
- Types of anoxia (without oxygen):
(1) Anoxic anoxia:
o lack of oxygen in the air
o Blockage of the airways
o Paralysis of respiratory muscles
o Obstruction of the blood flow to the lungs
(2) Anemic and stagnant anoxia:
o Pressure on the neck vessels (mechanical asphyxia)
o Chemically combined hemoglobin
o Hemolysis
o Hemorrhage
(3) Histotoxic anoxia:
o Lack of cellullar respiration – blockage of enzymes
- Stages Of Mechanical Anoxia Or Violent Asphyxia:
(1)Stage Of Forced Respiration:
-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 3-5 Minutes – Brain Ischemia.
- phases of violent asphyxia
• ‘Surprise respiration’ (‘respiration de surprise’)
• Voluntary stopped respiration (0.5-2 min.)
• Dyspnoe (60-150 s, the lost of consciousness at the end of this phase)
• Convulsions (up to 1.5 min.)
• Apnoe
• Cardiac arrest