Asphyxia — lack of oxygen in blood and tissues due to impaired or absence of exchange of oxygen and carbon dioxide on a ventilatory basis, leading to death.

15.1: Etiology of Asphyxia

• Physical causes: Breathing in high altitudes with rarefied/ vitiated medium, deficient of O2, e.g. mountaineering.

• Inhaling irrespirable gasses — such as gasses interfering with normal O2 carrying capacity of blood hemoglobin.

• Drugs/poisons: Directly depressing the respiratory centers, e.g. narcotics (morphine), anesthetics, etc.

• Mechanical asphyxia — this is due to mechanical interference to respiration, e.g. hanging, strangulation, throttling, smothering, choking, drowning, etc

• Pathological asphyxia — this is due to diseases, e.g. lung pathology.

• Allergic reactions causing laryngeal edema.

15.2: Anoxia

• Anoxia — asphyxia that leads to lack of oxygen supply to cells and tissues.

Gordon’s Classification of Anoxia

• Anoxic Anoxia: Here oxygen cannot gain entry into the blood.

• Anemic Anoxia: Here oxygen can get into blood, but the blood is incapable of carrying it.

• Stagnant Anoxia: Here oxygen can get into the blood, blood is capable of carrying it, but circulation is at failure, e.g. congestive cardiac failure.

• Histotoxic Anoxia: Here oxygen can get into the blood, blood is capable of carrying it, and the blood circulation is perfectly normal, but the cell cannot utilize the oxygen available in blood.

  • Extracellular histotoxic anoxia: Here oxygen cannot be taken up due to the failure of tissue enzyme system by poisoning.

  • Pericellular histotoxic anoxia: Here oxygen cannot be taken up due to reduced permeability of cell membrane.

  • Substrate histotoxic anoxia: Here oxygen cannot be taken up due to failure of efficient cell metabolism.

  • Metabolite histotoxic anoxia: Here oxygen cannot be taken up due to the accumulation of end products of cell respiration.

15.3: Clinical Effects of Asphyxia

15.4: Classification of Mechanical/Violent Asphyxia

1. Compression/ constriction of the neck.

2. Blocking external orifices of respiration.

3. Impaction of foreign bodies in the respiratory tract.

4. Compression and mechanical fixation of the chest and abdomen prevent respiratory movements.

5. Inhalation of fluid into the respiratory tract.

15.5: Hanging

• Hanging — Complete or partial suspension of the body by a ligature tied around the neck and force of constriction on the neck being applied by the weight of the body hanged.

Classification of Hanging

• Complete hanging — both feet are not touching the ground.

• Partial hanging — both feet or any other parts of the body are touching the ground.

• Typical hanging — knot of ligature is on the backside of the neck.

• Atypical hanging — knot of the ligature is anywhere other than on the backside of the neck.

Mechanism of Hanging

• Findings in the Face

  • Pallor / congestion

  • Lips may show cyanotic tinge.

  • Changes in the eyes

  • Prominent eyeballs: Eyeballs may look prominent due to increased as a consequence of impaired circulation and venous return resulting in passive accumulation of blood.

    • La-facie sympathique – described this peculiar change wherein the right eye remained open with a dilated pupil and the left eye closed with a small pupil.

    • Subconjunctival hemorrhages: Petechial hemorrhagic spots may be noticed with subconjunctival tissues and inner aspects of the eyelids.

  • Tongue may be protruded out due to pressure on the floor of the mouth by the ligature material from below, pushing the tongue out of the oral cavity.

  • Due to the impaired venous return and increase in pressure within, resulting in rupture of vessels and passive flow of the blood from nostrils and ears.

  • Dribbling occurs from the angle of mouth whichever is at lower level.

• Findings in the Neck

  • Distended neck veins

  • Ligature mark of hanging

  • A typical ligature mark is usually seenin antemortem hanging. It is also reported to appear if hanged immediately after death or within a period of 2 hours of death.

• Findings in Other Parts of the Body

  • Hands are usually clenched.

    • Hands may also show bluish discoloration of fingertips and nail beds due to cyanosis.

  • Purple coloured postmortem hypostasis is usually in a peculiar distribution in the lower limbs and lower regions of upper limb and at the upper margin of the ligature mark, which are actually lower parts of different body segments in this posture.

  • Involuntary voiding of urine and /fecal matter stains of which may be seen on the under garments/on the floor below.

  • Abrasions or contusions on lateral aspect of shoulder, feet, toes

  • In male victims:

    • Penile turgidity — penis may be found turgid and erect.

    • Seminal voiding — seminal emission may be noticed at the tip of the glans penis over the thighs of or seminal stains may be seen on inner garments, etc.

  • In female victims:

    • Apart from the voiding of urine and stools, turgescence of vagina with blood-stained discharge may also be noticed.

15.6: Internal Autopsy

• Findings in the lungs:

  • Lungs will be congested, distended and emphysematous with plenty of hemorrhagic spots subpleural.

  • Cut section usually exudes frothy fluid blood, if constriction occurs at the end of expiration.

  • It would be pale with little or no congestion, if constriction occurs at the end of inspiration.

• Findings in the heart:

  • The heart is congested and shows Tardieu’s hemorrhagic spots over the pericardium.

  • Right side of the heart, pulmonary artery and vena cava are usually found full with dark fluid blood, while left side empty.

• Findings in the brain: Brain and its membrane will be congested and with or without scattered petechiae on its surface and substance.

• Findings in abdominal viscera: All the abdominal viscera are congested.

• Blood changes: Blood will be fluid and purplish.

• Neck findings:

  • In every case of death by hanging, a careful dissection of the neck is done, layer by layer, so as not to miss any of the internal findings, confirming hanging as the cause of death.

  • This is possible only if the dissection area is maintained clean free from bleeding, which can be only achieved by a special technique called bloodless dissection of the neck.

Bloodless Dissection of Neck

• Bloodless Dissection of Neck — conducting the neck dissection at the end of autopsy examination, after performing dissection of cranium above and thorax and abdomen below, with removal of every other viscera except in the neck.

• Probable neck findings suggestive of antemortem hanging are:

  • Subcutaneous tissue underneath the ligature mark is dry, whitish, firm and glistening.

  • The platysma and the sternomastoid muscles may show petechial hemorrhages and may be ruptured occasionally.

  • There may be bruising in the subcutaneous tissue and the muscles, deeper to the mark.

  • Rupture or tears of intima of carotid arteries above its point of bifurcation, around the sinuses with extravasation of blood in their walls, especially in cases of a long drop, may be observed.

  • Trauma to hyoid bone and larynx—a brief discussion on forensic anatomy of hyoid bone and larynx is appropriate at this juncture.

• Hyoid Bone — a bone described as having a ‘U’ shape, with a central horizontal body; to which ‘greater horns’ are attached on either side by a natural joint.

  • The greater horns lie behind the sternomastoid muscle at its front part, 3 cm below angle of the mandible and 1.5 cm away from the midline.

• Larynx — a neck structure in the midline anteriorly.

  • In an adult male, it lies opposite the 3rd-6th cervical vertebrae, while in a female, it is at a higher position slightly.

  • It comprised nine cartilages; namely, thyroid, cricoid, epiglottis and smaller pairs of cuneiform, corniculate and arytenoids.

• Cricoid Cartilage — signet ring shape with signet part situated posteriorly.

  • It is rarely injured in hanging deaths because of its position and cartilaginous structure.

• Thyroid cartilage — made up of a shield-shaped body in the middle.

  • It is angled at about 90 degrees in a male and 120 degrees in a female.

  • Its location is being covered merely by fascia and skin, it is highly vulnerable to injury.

  • The superior horns are firmly attached to the hyoid bone by thyrohyoid ligament.

Mechanism of Fracture and Fracture Dislocation of Hyoid Bone

• Hyoid bone — usually reported to remain intact (90-95%). If fractured it is usually seen in age group of 40 years and above, at the greater cornu at the junction of inner two-thirds with outer one-third.

  • Antero-posterior compression fracture: Here the distal fragment gets displaced outwards and periosteum may be torn on the inner aspect.

  • Side-wise compression fracture: Here the distal fragment will be bent inwards and the periosteum may be torn on outer aspect.

  • Traction/Avulsion/Tug fracture – Here due to the powerful muscles attached to the upper and anterior surface of hyoid bone, it is drawn up and held rigidly.

• Fracture of thyroid cartilage: Fracture of superior horns of thyroid cartilage is common like greater horns in hyoid bone and this usually depends on state of ossification of these structures.

15.7: Medicolegal Aspects of Hanging

Homicidal Hanging

• This is very rare. It is virtually impossible to hang a healthy adult unless beaten to unconsciousness or rendered helpless by alcohol or drugs.

• Firstly, one may suspect homicide by virtue of the injuries on the victim.

• Secondly, there may not be any struggle marks on the body except noose mark or possible contusions of the arms, inflicted while being forcibly restrained to hang.

Homicidal hanging may be suspected when following findings are observed in the body hanged:

• Knot of the ligature is exactly on the back of the neck

• Mouth is gagged with cloth/paper

• Hands are tied on the backside of body

• Several injuries on the parts of body

Accidental Hanging

• Among infants — e.g. umbilical cord around the neck — this is also known as twisting of cord around the neck. This can cause the death of the fetus during birth or occasionally, immediately after birth from asphyxia due to accidental strangulation.

• Among children — e.g. while playing Lasso. Here the neck of the child may get entangled in a rope resulting in death due to asphyxia.

• Among adolescent/adults — e.g. Sexual asphyxia, popularly known also as “sex associated asphyxia, autoerotic hanging, asphyxiophilia, hypoxiphilia, Kotzwainism, masochistic phenomenon”, etc.

Judicial Hanging

• Cause of death in judicial hanging is due to injury to spinal cord in the neck because of the fracture and dislocation of upper cervical vertebra C and contusion or transaction of the underlying cord.

• In perfectly performed judicial hanging, the victim abruptly stops at the end of his fall when his head is jerked suddenly and violently backwards, fracturing his spine, known as hangman’s fracture.

Lynching

• Lynching is hanging of a victim who may be criminal by a mob.

• It is homicidal hanging.

• The people who get angry by the offence committed by the accused, kill him publicly by hanging to demonstrate the punishment given to him.

Difficulties in Diagnosis of Death from Hanging

• Ligature running around the neck of the victim might be killed first by strangulation and then hanged to simulate suicidal hanging.

• Presence of two-ligature marks might be an antemortem hanging case, but after a few minutes of hanging, it might have slipped further down producing a second ligature mark.

• Nail marks on the neck might look like manual throttling.

• Faint ligature mark may be seen in dark skin complexion people.

• Injuries on the body of the victim while inducing hanging might have injured him or herself (wide supra).

15.8: Strangulation

• Strangulation – a form of violent asphyxia caused by constricting the neck by some means, the force of constriction being other than weight of the victim's body.

Classification of Strangulation

1. Ligature Strangulation — it is when a ligature material is used to strangulate the victim.

2. Manual Strangulation (Throttling) — it is when bare hands are used to compress the neck and strangulate.

3. Mugging (Arm-Locks): Neck is compressed or squeezed by holding it between the crook of the elbow or knee. The attack is usually made from behind.

4. Bansdola: Neck is compressed between two bamboo sticks one held in front of the neck and the other behind it.

5. Garroting — a thin string is thrown around the neck of an unaware victim, from his back.

6. Palmar Strangulation — a combined from of violent asphyxia where in smothering and strangulation are performed together.

Medicolegal Aspects of Strangulation

• Virtually all strangulations whether ligature or manual are homicidal. There will be marks of violence, on other parts of the body.

• Though in ligature strangulation, females predominate as victims, it is not as much as reported in case of manual strangulation.

• It is reported that in ligature strangulation anything which can be twisted may be used as a suitable ligature material.

• Suicidal Manual Strangulation

• Suicidal Ligature Strangulation

15.9: Suffocation

• Suffocation — a form of asphyxia caused by lack of oxygen in the atmosphere or by mechanical obstruction to the air passages by mechanical means other than constriction of the neck and drowning.

Classification of Suffocation

• Entrapment — due to inadequate oxygen in the environment.

• Environmental suffocation: Here the individual inadvertently enters an area where there is gross deficiency of oxygen.

• Smothering — a form of asphyxia caused by mechanical occlusion of external air passages.

  • Overlaying — form of accidental smothering of an infant by the mother sharing the same bed with the child, may roll over it during sleep and occlude the air passages by her breast which the infant may be suckling, developing asphyxia and death.

  • Homicidal smothering:

    • Pressing the face and the nose by hand, towel, pillow, etc.

    • Tying plastic bag or such other materials around the mouth and nose.

    • Pressing the face of the victim over ground.

  • Suicidal Smothering:

    • Tying a plastic bag around the head covering the mouth and nose and tightening it by applying multiple knots until the person loses consciousness.

    • Tying a pillow in front of the face with application of several knots until it loses consciousness.

• Choking — a form of asphyxia caused by mechanical occlusion within various sites of upper air passages by foreign objects.

  • A solid object like a metallic coin, edible fruit seed, toffees, candies, spherical solid sweets, etc.

  • A food particle like bolus of rice particles, fish and any other animal bone, etc.

  • Piece of cloth like handkerchief, sari or dhoti material stuffed into the mouth tightly occluding the air passages.

  • Tongue of the person who is in an epileptic attack may fall back onto the posterior pharyngeal wall.

  • Sucking a piece of balloon to puff it or inflate it inside the mouth may result in occlusion of larynx when sucked into it accidentally when the grip on the balloon is not firm.

• Gagging — a means to affect choking by preventing the air entry into the respiratory tract by stuffing gag material into the mouth.

• Traumatic asphyxia — a form of asphyxia resulting from trauma of the chest leading to forceful compression of the chest preventing respiratory movements.

• Positional Asphyxia: The victim here gets trapped in restricted spaces, where because of the position of the body they cannot move out of that area or position.

• Riot-Crush — it is when the thoracic wall is compressed by stampeding people piling on top of each other.

• Burking — a combination form of smothering/palmar strangulation and traumatic asphyxia, resulting in death.

• Suffocating gases: Suffocated due to chemicals or gases around the environment.

15.10: Drowning

• Drowning — a form of violent asphyxial death, wherein the entry of air into the lungs is prevented by water or other fluids due to the submersion of mouth and nostril.

Causes of Death in Drowning

• Electrolyte imbalance (due to fresh/salt water drowning)

• Cardiac arrhythmias

• Vagal inhibition

• Laryngeal spasm

• Head injury during fall in water

• Apoplexy

• Exhaustion

• Infection

Mechanism of Drowning

Classification of Drowning

1. Typical Drowning — also known as ‘Wet Drowning’. Here there is actual obstruction of the air passages by the fluid or water column entering into it.

2. Atypical Drowning: Here there is very little or no fluid or water which is inhaled into the air passages. It includes four subtypes:

   • Dry drowning: Here no water is detected in the lungs during autopsy examination. Lungs remain dry and water free.

   • Immersion syndrome: It is usually found in temperate or cold zones, where usually young swimmers are the victims. When they dive in very cold water, they may suffer from vagal inhibition of the heart and die sudden death in water, even though they may be good swimmers.

15.11: Postmortem Findings of Drowning

External Findings

1. Findings in the Face

   • Face is congested and livid.

   • Eyes:

     • Palpebral fissure — open/closed (half)

     • Conjunctivae — congested

     • Pupils — dilated

   • Tongue - swollen and protruded out

   • Mouth and nostrils - show fine froth collected around, which may be whitish, shaving cream lather like.

2. Findings in the Skin

   • Cutis anserine (goose skin appearance): Here the skin appears like an orange peel.

   • Postmortem lividity

3. Findings in the Hands

   • Cadaveric spasm (instantaneous rigor) — Here the hands of the deceased would be clenched and on opening may show water, plants, seaweeds, etc.

   • Washerwoman’s hands — A specific change that is seen in the skin of the palm and sole, which consists of wrinkled, swollen, whitish sodden appearance, constitutes washerwoman’s hands.

   • Skin of the sole of the feet may also present with similar changes as seen in the hands, constituting washerwoman’s feet.

   • Rigor mortis

   • Bodies cool much more rapidly in water than in air. The process of decomposition of bodies in water takes a longer duration.

4. Leaching out of blood from antemortem wounds

Internal Findings

• Lung Findings

  • Typical drowning cases — Change due to typical drowning is called emphysema aquosum.

    • Lungs will be pale and grayish, voluminous, edematous, and bulging out like a balloon on cutting open sternum.

    • Streaming out of fine froth, blood with sand, mud and slit particles in the trachea, bronchi and bronchioles are the usual observations in the cut section of the lung, in favor of death due to drowning.

  • Atypical drowning cases: In case of say a victim who is unconscious at the time of drowning the findings are known as edema aquosum, which will never be the same as in typical drowning cases.

• Middle Ear Findings: While in drowning due to the violent attempts made by the victim to breathe in air, water also gets aspirated with air into the naso/ oropharynx, which forces little water into the middle ear also.

• Hemorrhage in Petrous Temporal and Mastoid Bone

• Changes in Heart

  • The right ventricle may show dilatation.

  • Changes in the heart basically refer to biochemical changes in the heart blood.

• Findings in Stomach: May contain the water swallowed along with the various contents in it, such as mud, algae (diatoms), planktons, etc. detected microscopically.

• Diatom Test

  • This is a more exotic, though controversial test which involves the identification of diatoms in tissues of drowning victims.

  • Diatoms are microscopic unicellular algae which live in water.

  • They vary in size (5 to 400 μm) and shape and have got a hard-cell wall made of silica, which resists acid digestion.

Medicolegal Aspects of Drowning

• At autopsy, there are no pathognomonic findings to make the diagnosis of drowning.

• The diagnosis is based on the circumstances of death, plus a variety of nonspecific anatomical findings.

• Chemical tests put forth to make the diagnosis are nonspecific and essentially unreliable.

• If an individual is found dead in water and all other causes of death have been excluded, he is presumed to have drowned.

• It must be remembered that people who have had fatal heart attacks and fallen into the water, and that disposal of a victim of a fatal drug overdose in water is not unknown.

• Attachment of heavyweights to the body to keep it underwater is consistent with both homicidal and suicidal drowning, as well as disposal of the body of a person who died of some other cause.

• Position and flotation of a dead body in drowning – when a person drowns, the body sinks, assuming a position of head down, buttocks up, and extremities dangling downward.

• Depending on how long the body was in the water, there may be evidence of animal activity, for example, fish, turtles, crabs, or shrimp.

• Drowning in bathtubs is relatively uncommon. Usually involves young children unattended by parents. Some are undoubtedly homicidal as well.

• Scuba Divers deaths can occur with the use of scuba diving equipment, and may be caused by natural diseases, as a consequence of being underwater at increased pressure.