FM2.17-19,FM3.1-4 | Asphyxial Deaths & Deaths from Physical Agents — Glossary

A systemic illness following significant whole-body ionising radiation exposure; progresses through prodromal, latent, manifest illness, and recovery/death phases; haematopoietic failure at 2–6 Gy; above 6 Gy without support is typically lethal.

Condition arising from mechanically-induced interference with respiration, leading to deficient oxygen supply and accumulation of carbon dioxide in the blood and tissues, culminating in death if uncorrected.

Sudden death from acute laryngeal obstruction by a food bolus, most commonly in elderly persons with poor dentition or in an inebriated state; mimics cardiac arrest.

Haemoglobin combined with carbon monoxide from fire smoke; levels above 10–15% indicate significant exposure; levels above 50% are typically lethal; its presence in blood is the most reliable indicator that a fire victim was alive and breathing during the fire.

The documented record of everyone who handles a piece of physical evidence from the scene through the laboratory to court; essential for the admissibility of forensic evidence; initiated when the forensic physician seals and labels the ligature material.

Internal airway obstruction by a foreign body at the larynx, trachea, or bronchus; usually accidental; café-coronary syndrome is the archetypal form.

The hallmark PM finding of throttling — small, curved cuts produced by the assailant's fingernails digging into the neck skin during manual strangulation; their distribution can indicate the number of hands used and the direction of attack.

Blue-purple discolouration of the skin and mucous membranes resulting from the presence of deoxygenated haemoglobin in peripheral capillaries; present in most asphyxial deaths but not specific to them.

Forensic test for ante-mortem drowning based on finding diatom frustules (silica-walled algae) in bone marrow and distant organs (liver, kidney, brain), requiring vital circulation for their systemic distribution.

Unicellular photosynthetic algae with characteristic silica cell walls (frustules) resistant to acid digestion; found in virtually all natural water; their presence in distant organs at PM indicates they were circulated by a beating heart — i.e., ante-mortem aspiration.

A process resulting in primary respiratory impairment from submersion or immersion in a liquid medium; encompasses wet drowning (water aspirated), dry drowning (laryngospasm), secondary drowning, and immersion syndrome.

Drowning in which laryngospasm prevents water from entering the lungs; death is from asphyxia with dry lungs at PM; triggered by cold or very clean water; accounts for ~10–15% of drowning deaths.

The characteristic entry wound of domestic/industrial electrocution: a small, oval, punched-out lesion with a pale or yellow-white centre (coagulation necrosis) surrounded by a red rim (reactive hyperaemia); a corresponding exit wound is present where the current left the body.

Over-inflated, waterlogged, oedematous lungs characteristic of wet drowning; lungs are heavier than normal, pale or mottled, and exude fluid on sectioning; Paltauf's haemorrhages (pale subpleural haemorrhages) may be present.

Localised cold injury from tissue freezing; classified in four degrees mirroring burns; affects extremities and exposed peripheral areas; PM shows dry, mummified, black necrotic tissue.

A device used in ligature strangulation involving a cord and a twisted stick or lever to apply sustained compressive force around the neck; both the cord and the garrotte stick must be preserved as evidence.

A historical forensic test based on differential chloride concentration between left and right heart blood; in freshwater drowning, left heart blood is more dilute (lower chloride); in saltwater drowning, left is more concentrated; now largely superseded by the diatom test.

Asphyxia caused by neck compression where the compressing force is the weight of the body suspended from a ligature; the ligature mark is above the thyroid cartilage, oblique, and discontinuous at the knot.

Fracture-dislocation of C2 on C3 occurring only in judicial long-drop hanging, producing instantaneous spinal cord transection and death; does NOT occur in suicidal or accidental hanging.

Painful muscle cramps from salt depletion after excessive sweating without sodium replacement; temperature is normal or mildly elevated; occurs in labourers and athletes; treated with salt and fluid.

Volume-depletion heat illness with dehydration, tachycardia, hypotension, and elevated temperature typically below 40°C; consciousness is maintained, distinguishing it from heat stroke; reversible with fluid and cooling.

Severe heat illness with core temperature >40°C, failure of thermoregulatory sweating (anhidrosis in classic form), and CNS dysfunction; a medical emergency with multi-organ failure; identical pathophysiology to sun stroke (solar-precipitated form).

Fracture of the U-shaped hyoid bone at the base of the tongue; more common in throttling and in older individuals with ossified hyoid than in hanging; its presence suggests substantial neck compression but its absence does not exclude strangulation.

Sudden cardiac arrest from vagal stimulation triggered by cold water contact (cold shock reflex); the victim dies before significant water aspiration; lungs are relatively dry at PM; not true drowning by the WHO definition.

A form of hanging where part of the body remains in contact with a surface (kneeling, sitting); the partial body weight is sufficient to compress neck vessels and cause death; accounts for many suicidal hangings in India where low suspension points are used.

Indian Penal Code provision for causing death by negligence (not amounting to culpable homicide); applicable in accidental crush asphyxia where gross negligence of a duty-holder (crowd management, industrial safety) can be established.

Branching, fern-like, arborescent skin markings produced by a lightning flashover discharge; PATHOGNOMONIC of lightning; appear within hours and fade within 24–48 hours; must be photographed immediately at PM.

A brownish, dry, firm abrasion left by the ligature on the skin of the neck; in hanging it is oblique and discontinuous; in ligature strangulation it is horizontal and continuous; becomes leathery and parchment-like post-mortem due to drying.

Compression of the neck by a ligature where the force is applied externally (typically by another person); mark is at or below the thyroid cartilage, horizontal, and continuous; almost invariably homicidal in adults.

Intense violet-blue discolouration, petechiae, and oedema of the face, neck, and upper chest with a sharp lower border, produced by retrograde transmission of raised intrathoracic pressure through valveless jugular veins in traumatic/crush asphyxia.

Persistent, fine-bubbled, white froth at the nostrils and lips produced by the churning of air, water, and mucus during active respiratory efforts in drowning; a strong indicator of ante-mortem drowning; absent in post-mortem immersion.

Asphyxia resulting from a body position that mechanically restricts respiratory movement; common in intoxicated or neurologically impaired individuals; prone restraint is a well-recognised risk context.

The flexed 'boxer's posture' adopted by a body in fire; produced by post-mortem heat coagulation and shortening of flexor muscle proteins; NOT a sign of ante-mortem struggle or vital reaction.

Delayed pulmonary oedema occurring hours after near-drowning rescue, due to surfactant loss and alveolar inflammation from aspirated water; can be fatal 1–24 hours after the victim appears clinically stable; requires hospital observation for ≥24 hours after any drowning incident.

Deliberate self-induction of cerebral hypoxia during sexual activity to enhance arousal; almost exclusively male and solitary; death is accidental — the individual fails to release themselves in time.

External obstruction of the nose and mouth preventing air entry; the asphyxiating force is applied to the face; characteristic forensic setting in infanticide and elder homicide.

Core body temperature below 35°C; graded mild (32–35°C), moderate (28–32°C), severe (<28°C); PM finding includes Wischnewski gastric spots; severe cases may mimic death and require active rewarming before death can be confirmed.

Petechial haemorrhages (1–2 mm) on the visceral pleura, epicardium, and meningeal surfaces resulting from rupture of overdistended terminal venules during the convulsive phase of asphyxia; a sensitive but non-pathognomonic sign of raised venous pressure.

Manual strangulation by the hands; fingernail crescent abrasions and fingertip oval bruises on the neck are pathognomonic; always homicidal in adults.

Asphyxia caused by external compression of the thorax preventing respiratory excursion; classic PM sign is the masque ecchymotique (traumatic cyanosis of the face and upper chest).

Evidence of living tissue response to thermal injury: hyperaemia, serum-rich blistering (with protein and leucocytes), neutrophilic infiltration at the burn margin, and (systemically) soot in the airways and carboxyhaemoglobin in the blood; its presence confirms ante-mortem burn; its absence in a burn victim suggests post-mortem fire exposure.

Pale, sodden, wrinkled maceration of the skin of the palms and soles from prolonged water immersion; develops within 30 minutes of warm water immersion; NOT specific to ante-mortem drowning.

The most common form (~85–90%); water is aspirated into the airways during submersion, producing waterlogged, over-distended lungs (emphysema aquosum) at post-mortem.

Reddish-brown haemorrhagic erosions in the gastric fundus; a characteristic internal PM finding in deaths from systemic hypothermia, resulting from ischaemia-reperfusion injury to the gastric mucosa.