Forensic Pathology Quiz

Asphyxia is the deprivation of oxygen.
Asphyxial death is the death caused by a lack of oxygen.
Learning objectives for the lecture include identifying types of violent asphyxia deaths, mechanisms of infliction, postmortem appearance, and medico-legal significance for hanging, strangulation, throttling, smothering, choking, and traumatic asphyxia, and diagnosis of traumatic asphyxia.

Violent asphyxial deaths include hanging, strangulation, throttling, strangulation, smothering, and choking.
Types of hanging include complete, partial, typical, and atypical, categorized further by ligature support or not, and site.

Hanging is an asphyxial death caused by suspension by a ligature around the neck.
Force is derived from gravitational weight.
Types include complete (feet off the ground), partial (feet or knees touch the ground), atypical (ligature position below thyroid cartilage), and typical (ligature position above the thyroid cartilage, runs symmetrically upwards on both sides of the neck).
Forms of ligatures include loops (knotted "fixed knot") and running noose (pass through the loop "slip knot").

Cerebral anoxia (anemia) due to constriction force exerted on the neck, stretching of the neck structures including the carotid arteries, causing their occlusion.
Cerebral congestion or apoplexy resulting from occlusion of neck veins such as the external and internal jugulars, leading to a rise in venous pressure in the head.
Asphyxia from direct compression of larynx or trachea, lifting of the larynx, causing the tongue to close the root of the tongue, and reflex vagal inhibition (cardiac arrest) due to pressure on baroreceptors in the carotid sinus and carotid body.
Injury to the spinal cord, especially in judicial hanging, which can lead to fracture and/or dislocation of the third and fourth cervical vertebrae.
Death can be caused by combination of these factors

Neck: Stretched, head inclined to the opposite side of the knot.
Face: Pale, congested, swollen (incomplete carotid arteries obstruction), prominent eyeballs, swollen/protruded tongue, exposed part may become dark brown or black due to dryness.
Saliva: May dribble from the corner of the mouth opposite the side of the knot due to pressure on salivary glands.
Hyoid bone: Possible fracture

Shape: Ligature mark shape (upper and lower).
Color: Pale yellow or yellowish brown.
Situation: Position of the ligature mark above or below the thyroid cartilage..
Direction: Typically transverse and slightly upwards.

Absence of fatal injuries or poisoning
Presence of dribbled saliva
Congestion/hemorrhage in lymph nodes
Tear of carotid artery intima with extravasations
Suicide: History of failure, depression, psychic troubles, suicidal note, calm location, and signs of previous attempts like wrist cutting
Homicide: History of threatening/quarrels, signs of struggle, gagged mouth and the knot tied on the back of the neck, evidence of drugs/alcohol
Accidental: Children playing with ropes, adults' neckties caught in machinery, or toddlers slipping from restraints

Form of violent asphyxia caused by neck constriction by hand.
Body weight plays no role.
Mechanism of death likely a combination of asphyxia, reflex vagal inhibition, and cerebral anoxia.
Postmortem characteristics include nail abrasions, bruises, fractures of laryngeal cartilages.

The same facial findings as in hanging.
Neck signs include nail abrasions, bruises, and swelling (around neck)
If one hand is used, a single bruise is observed on one side of the neck (often the thumb point), with multiple bruises on the other side of the neck (fingers).
If both hands were used, multiple bruises or marks are likely on both sides of the neck, with lesser injuries seen if intervening clothing is present between the assailant's hand and the victim's neck.

Mechanical occlusion of air passages from the outside.
Postmortem characteristics include general signs of asphyxia, and presence of struggle marks in cases of homicidal smothering.
Nail and abrasion marks are found around the nose and mouth.
Physical wounds may be inside the lips and cheeks, and a torn frenulum, loose or broken teeth, and fracture nasal septum.

Mechanism of death related to asphyxia, reflex vagal inhibition, and pulmonary infection.
Postmortem appearance: common accidental causes (impacted food, etc.), struggles marks in case of homicide, and the presence of foreign bodies in the airway for causes like choking on food.

Obstruction of larynx caused by a bolus of food.
Mimics a heart attack.
Typically occurs with the gag reflex suppressed (e.g., tranquilizers and alcohol).
Mechanism leads to reflex cardiac arrest from stimulation of laryngeal nerve endings.

Violent asphyxia caused by trauma to the chest or abdomen resulting in prevention of respiratory movements.
Cases include homicide(e.g., burking), accidental (e.g., injury in road traffic accidents, heavy objects falling, chest compression during a crowd).
Postmortem characteristics: signs of chest trauma (fractured ribs, hemothorax), deep cyanosis, petechial hemorrhages, and a demarcating line around neck.