Dr. Hammad's document discusses asphyxial deaths and their classification. It covers various types of asphyxia including mechanical asphyxia caused by suffocation, hanging, and strangulation. Autopsy findings for each type are described, such as ligature marks and petechial hemorrhages. Causes of death include anoxic anoxia and reflex cardiac arrest. Homicidal, accidental, and suicidal cases are addressed. Drowning is also discussed, distinguishing between wet and dry types. In summary, the document provides a comprehensive overview of classifications, mechanisms, autopsy findings, and medicolegal aspects of asphyxial deaths.

1. ASPHYXIAL DEATHS
Dr. M. Hammad
Department Of Forensic Medicine
Asphyxia
 Commonly means “Lack of Oxygen”.
 In Greek meaning applying “Pulselessness/absence of pulsations
 It is defined as interference with the process of oxygenation in the lungs.
In Forensic context Asphyxia: Air is physically prevented to enter the air passages at
any part from nose and mouth to the alveolar membranes.
Classification of Gordon
1. Anoxic anoxia
2. Anaemic anoxia
3. Histotoxic anoxia
4. Stagnant anoxia
 Anoxic anoxia
 1. By obstruction to air passages
 Suffocation, Smothering,
 2. By obstruction to the air passage down to the respiratory tract
 Drowning, Choking, throttling, hanging and strangulation
 3. Excessive compression of the chest and abdominal wall
 4. Primary cessation of respiratory movements causing respiratory failure
as in narcotic poisoning , electrical injury
 5. Inhalation of irrespirable gases
CO2 and CO
 Anaemic anoxia
Reduced oxygen carrying capacity of the blood.
 Histotoxic anoxia
 Depression of the oxidative process in the tissues.

2.  As in hydrocyanic Acid poisoning.
 Stagnant anoxia
 Insufficient circulation of the blood in the tissue,
 As in traumatic shock,
Classification of Asphyxia
 Mechanical asphyxia
 Pathological asphyxia
 Toxic asphyxia
 Environmental asphyxia
 Iatrogenic asphyxia
Mechanical asphyxia
 Obstruction of air passages in an unnatural way either from within or by exerting
pressure from the outside.
 These includes;
1. Suffocation
2. Hanging
3. Strangulation
4. Sexual Asphyxia
5. Drowning
Pathological Asphyxia
 Transfer of oxygen to the lungs is prevented due to blockage caused by any
disease.
Toxic Asphyxia
Uptake of oxygen is prevented in the lungs due to presence of some poisonous gases
like carbon monoxide.
Environmental Asphyxia
 Insufficiency of oxygen in the inspired air
(Deep wells or closed spaces)

3. Iatrogenic Asphyxia
 Associated with Anesthesia and surgery
Physiology of Fatal Asphyxia
 It has three phases of short durations.
 Unconsciousness occurs in about one minute followed by death in about 2-4
minutes.
Phases of Fatal Asphyxia
 Phase –I initiates with the stimulation of the respiratory center increasing both
rate and amplitude of the respiratory movement. Cyanosis begins to appear.
 Phase – II Is characterized by struggle to breath. The cyanosis deepens with
engorgement of the neck veins. Generalized congestion and Petechial
hemorrhages start appearing. The victim becomes confused and later goes
unconscious
 Phase – III  unconscious, which leads to the coma. Breathing becomes irregular
, shallow, gasping.
Biochemistry of Fatal Asphyxia
 PO2 reduced.
 PCO2 increased.
 pH decreased.
 Increased Blood sugar.
 Na decreased.
 K increased.
Pathology of Fatal Asphyxia
 Nonspecific pathological changes
 Specific pathological changes

4. Nonspecific pathological changes
1. Visceral congestion & congestion of face.
2. Oedema
3. Petechial haemorrhages
4. Cyanosis
5. Postmortem fluidity of blood.
6. Cardiac dilatation
Congestion
 Red appearance of the skin due to obstruction of venous drainage.
Oedema
Swelling of the tissues due to transudation of fluid from the veins.
Cyanosis
 Blue color imparted to the skin by deoxygenated blood.
Petechial haemorrhages
 Tiny pin point hemorrhages in the skin/tissue due to damage of vessels and
leakage of blood by increased venous pressure.
Also seen in violent sneezing and coughing…
Specific pathological changes
1. Signs of compression of upper airways as in hanging, strangulation & throttling.
2. Occlusive blockage of the mouth & nose as in smothering.
3. Presence of foreign body as in choking.
4. Flooding of airways as in drowning.
5. Penetrating & non penetrating trauma to the chest as in traumatic asphyxia
Suffocation ,Hanging, Strangulation
Suffocation

5.  It is defined as manual obstruction to the air passage caused by closing of the
external orifices of Nose & mouth.
Types
1. Smothering
2. Gagging
Smothering
 Smothering is defined as closing of air passages externally either by hands or by a
soft material.
 Mechanism of suffocation
Anoxic anoxia
ML importance
 Accidental
 Homicidal
 Suicidal
Accidental smothering
 Overlaying:-
 Infants & children it is defined as smothering of the child by overlaying their
mother during sleep.
 It also occurs in inexperienced mother presses the child too closely to the breast
when feeding the baby.
Accidental smothering
 Alcoholics: In inebriated state of mind roll over and bury their face in soft bed.
 In Epileptic: when a person suddenly falls into a bin of dust or flour.
Homicidal
 Killing of infants by smothering & gagging

6.  In adults – not common
 Burke & Hare in Scotland– 1820’s (To supply the dead bodies to Edinburgh
medical school for anatomical dissection.)
 Burking  Burke sat on the chest of victim, covered with one hand victims
mouth & nostrils and with the other hand pushed the jaw upwards while Hare
hold legs of victim.
Autopsy findings in Smothering
 External Autopsy findings:
 When hands have been used 
 Nail scratches, Abrasions, Bruises(especially the fingertips bruises), lacerations of
the soft parts of the face.
 Lips gums and tongue may show bruising and or laceration.
Bruising on the inner aspect of lips from pressure against the teeth, with or
without bruising of the gums and tongue.
 When some clothing, soft material or pillow has been applied  There may be
no external signs of violence
 Internal Autopsy findings
 Lungs may show edema, congestion and areas of Petechial hemorrhages.
 Blood should be examined for drugs.
Gagging
 Gagging is stuffing of mouth with a cloth or with any soft material and blocking
entry of air into these passages.
 It may be homicidal, particularly when victims are infants or individuals
incapacitated by alcohol or drug, old,
 Gag not only blocks the mouth but also prevents the entry of air through the
back of throat coming through the nostrils.

7.  Death in such cases is due to pharyngeal obstruction
Autopsy findings in Gagging
 Autopsy findings depend upon the intensity of struggle to breath and some time
may be negligible or absent.
 If gag has been removed , mucosal bruising , abrasions or lacerations,
individually or in varying combinations, may be evident on the lips, soft palate
and in the pharynx.
 There may be present traces of the material in the mouth and between the
teeth.
Choking
 It refers to the blockage of internal upper respiratory passages by some
solid/semi-solid material.
 Impaction of foreign body in pharynx, larynx, trachea or bronchi.
 Common agents may be;
 Piece of food, lump of meat, coins, buttons , set of false teeth, marbles, corns
etc.
 In epileptic , tongue falling back
Mechanism of death
1. Anoxic anoxia
2. Reflex cardiac arrest  vagal inhibition.
3. Laryngeal spasm
 Foreign body in the respiratory tract especially in the bronchi may result in
delayed deaths from pneumonis, lung abscess or bronchiectasis.
Medicolegal importance
 Mostly accidental

8.  Children often place objects such as marbles, coins, buttons or beads in their
mouth and these objects may pass in to larynx or trachea during inspiration.
 In case of stupor (partial or nearly complete unconsciousness) Ex. From acute
Alcoholic intoxication vomited material may be inhaled and result in choking.
 Mentally ill & intoxicated person a portion of food bolus in the mouth may trickle
down into the air passages & block it.
Café Coronary Syndrome
 Is a condition of accidental choking where a bolus of food produces a complete
obstruction of the larynx.
 It is so called because it mimics a heart attack.
 Death in these cases is usually due to reflex cardiac arrest.
 Iatrogenic choking  May result from loose teeth during dental procedures,
detached pieces of tracheal cartilage during tracheostomy or surgical swabs
during surgery on the throat which may go down in to the larynx & trachea.
 All such cases may lead to criminal negligence.
 Homicidal deaths  uncommon
 Suicidal choking is very rare
Autopsy findings
 Non specific general pathological asphyxial changes
 Mouth , pallet & pharynx should be examined for injuries
Hanging
 It is defined as constriction of the neck by a ligature, after suspension in air. The
constricting force is the weight of the body.
Types of Hanging
 On the Basis of position of the Knot
 Typical hanging

9.  Atypical hanging
 On the Basis of degree of suspension
 Complete hanging
 Partial hanging (incomplete hanging)
On the Basis of position of the Knot
 Typical Hanging: when the knot is present over the occipital region.
 Atypical Hanging: when the knot is present at ant other point.
On the Basis of degree of suspension
 Complete Hanging: When feet do not touch the ground and the weight of the
body acts as constricting force.
 Partial or Incomplete Hanging: When feet touch the ground and the weight of
the head and partial weight of body act as constriction force.
Pressure needed to occlude neck structures
 According to Brouardel:
 Jugular veins ------------- 4.4 pounds ( 2kg)
 Carotid artery ------------11 pounds (4-5 kg)
 Trachea ------------------ 33 pounds (15 kg)
 Polson & Gee have confirmed these findings.
Mechanism of death
 Cerebral congestion  due to compression of the jugular veins
 Cerebral anoxia  by compression of carotid arteries
 Hypoxic hypoxia /Anoxic anoxia due to obstruction to airways being caused by
the upward displacement of the base of the tongue against the palate & the
posterior pharyngeal wall.

10.  Reflex cardiac arrest caused by compression of the carotid sinus or the vagus
nerve.
 Fracture displacement of cervical vertebrae injury to the spinal cord especially
in judicial hanging
Combination of any of above.
Fatal period
 Judicial hanging  It is instantaneous from fracture dislocation of cervical
vertebrae usually the 3rd
& 4th
and rarely the 2nd
one.
 Reflex cardiac arrest  immediate
 Otherwise  3- 5 min (8 min)
Autopsy findings
External findings:
 Neck is stretched
 Congestion of face, head and neck.
 Petechial hemorrhages
 Lips, nose, fingers are cyanosed
 Tongue dry, protruded, bluish or black.
 Dribbling of saliva  due to pressure on the salivary glands.
 Postmortem Lividity
Specific findings
 Ligature mark
 Type: ropes, wires, belts, electric cords, piece of cloth.
 Site: above the thyroid cartilage (80%)
 Knot: single or multiple with fixed noose or a running noose
 Direction: upwards, backwards and inverted V shaped.

11.  Ligature mark absent at site of knot.
Groove: pale, yellow brown, dry, hard and parchment like.
Pattern of ligature may imprinted on skin as pressure abrasion called mirror
image phenomenon.
Edge: congested and hyperemic.
Head inclined opposite side to the knot.
Internal findings
 Bruising of the connective and muscular tissues
 Under surface of the ligature mark
 Injury is more severe in judicial hanging
 Fracture of hyoid bone
 Fracture of laryngeal cartilages
 Hyperemia of trachea, epiglottis and lymph nodes
MEDICOLEGAL ASPECTS
Ante mortem or post mortem
Homicidal ,suicidal or accidental
o Ante mortem hanging
 Presence of abrasions
 Vital reaction
 Area of hyperemia or ecchymosis
o Suicidal hanging
 Common in females
 Signs of struggle are absent.
 Scene of crime – no disturbence

12.  History of depression, anxiety, family and economic problems.
 Calm place,
 Locked inside
 Suicidal notes.
o Homicidal hanging
 Rare
 In cases of judicial hanging (justifiable hanging ) & lynching (non justifiable
hanging)
Accidental hanging
 Uncommon
 Sexual asphyxia or auto erotic hanging
Auto erotic asphyxia
Sexual pleasure can be achieved by partial reduction of blood supply to the brain.
 Sexual deviation
 More common in males
 Abnormal sexual behavior like masochism and transvestism.
 Psychological autopsy
Hallmarks
 Padding under noose
 Naked or sami-naked
 Feminine attire
 Pornographic literature
 Drug abuser.
STRANGULATION

13.  Violent asphyxia caused by constricting the neck by some means other than
weight of the body
Types
 Ligature strangulation
 Throttling , manual strangulation
 Mugging
 Bansdola
 Garroting
Autopsy findings
Non specific
 Cyanosis
 Visceral congestion
 Petechial hemorrhages
 Swollen, bruised, bitten & protruded tongue
 Bleeding from the ears
 Raised body temperature by 2-3 C
Special
 Ligature mark
 Depressed grooved
 Color
 Continuity
 Position of knot
 Number of turns
 Pattern (Mirror image phenomenon)

14.  Injuries to the soft tissues of neck
 Fracture of hyoid bone
 Fracture of laryngeal cartilages
THROTTLING
 Constriction of the neck of a person by another person with one or both hands. It
is also called manual strangulation
MECHANISM OF DEATH
 Hypoxic hypoxia or anoxic anoxia
 Reflex cardiac arrest
 Cerebral anoxia
AUTOPSY FINDINGS
NON SPECIFIC
 Facial congestion
 Cyanosis
 Petechial hemorrhage
 Visceral congestion
 Tongue bruised
 Bleeding from ear
 Body temperature raised
Specific pathological changes
 External injuries
 With one hand or two hands
 Superficial bruises of skin & crescentric abrasion caused by fingernail impressions
on both sides of neck

15.  Right handed or left handed compression.
 Injuries to the cervical tissues
 Bruises
 Section of lymph nodes show hemorrhages
MEDICOLEGAL ASPECTS
a. Homicidal
b. Accidental
TRAUMATIC ASPHYXIA
 Also called crush asphyxia
 Is form of asphyxia resulting from trauma to the chest, person is unable to
breath.
Autopsy findings
 Deep cyanosis of face
 Numerous petechiae
 A demarcating line
DROWNING
 Defective oxygenation of the lungs due to the presence of fluid in the respiratory
tract.
 Medium of drowning
 Water
 Oil
 Dye
 Chemical solution

16. Types of drowning
 Typical (Wet type)
 Atypical (Dry)
*Dry drowning
*Immersion syndrome ( vagal inhibition).
*Submersion of unconscious.
 Secondary
Dry / Atypical drowning
 15-20%
 When no water enters into the lungs and death occurs by laryngeal spasm.
 Death is instantaneous
IMMERSION SYNDROME
(vagal inhibition, Hydrocution)
 Death results from cardiac arrest due to vagal inhibition.
 Produces by:
 Cold water
 Falling into water with feet first
 Duck diving
 Diving horizontally
WET DROWNING
 Mechanism is different in fresh water or sea water
In fresh water
Large volume of water into lungs then blood.
Hemodilution
Hypervolemia

17. Hemolysis of RBCs
Rise in the level of potassium
NaCl , Ca2+
, proteins & Hb are reduced
The hypoxia & hemodilution result into the ventricular fibrillation
Fatal period is 3-4 minutes
Drowning in sea water ( NaCl-3%)
Rapid diffusion of salts into the blood
Increase in NaCl & Mg2+
Fluid moves into lungs
Hemo concentration
Fulminant pulmonary edema
Hypotension
Hypovolemia
Bradycardia & death
Fatal period 7—9 min.
SECONDARY DROWNING
(NEAR DROWNING)
 Person survived and death is due to complications.
 Metabolic acidosis
 Hypoxic encephalopathy
 Chemical pneumonitis
 Severe infections
Mechanism
a. Period of voluntary apnea
b. CO2 level raised

18. c. Respiratory centre stimulated
d. Inevitable inspiration
e. Inhalation of water into lungs
f. Swallowing of water into the stomach
g. Specific gravity of body is raised & body sinks below surface
h. Respiratory efforts continues.
i. Filling of air passages and lungs with water.
j. Water acts as an irritant.
k. Secretion of mucous
l. Water, respiratory mucous and air churned up.
m.Fine froth.
Causes of death
1. Anoxia / hypoxia
2. Laryngeal spasm
3. In fresh water drowning  ventricular fibrillation
4. In sea water  cardiac arrest
5. Vagal inhibition
6. Hypothermia
Autopsy findings
 External appearances:
 Wet clothes.
 Skin is wet, cold ,clammy and pale.
 Face cyanosed
 Eyes :semi open or closed. Conjunctivae congested & pupils dilated
 Hypostasis on the dependent parts
 Rigor mortis
SIGNS OF GREAT IMPORTANCE
 Fine froth(champignon de mouse) at mouth & nostrils (froth is not seen when
death result from laryngospasm )
 Presence of weed, mud in tightly clenched hands (instantaneous rigor/cadaveric
spasm)

19. Signs of submersion
 Goose skin (cutis anserina)
 Sodden & wrinkled feet & hands (washer women’s hands)
INTERNAL APPEARANCE
 Special pathological changes in wet drowning
 Edema aquosum (emphysema aquosum or trockenesodem). Ballooning of lungs.
 Impression of ribs
 Surface pale
 On section, blood stained frothy fluid.
 Tardieu ‘s spots(paltauf ‘s hemorrhage) it is sub-pleural haemorrhages due to
rupture of alveolar walls.
 Fluid in pleural cavities
 Fine blood stained white froth
 Foreign materials like algae, weeds, mud, sand depending on the medium of
drowning
 Regurgitated particles of food
 Heart
 Right Heart & large veins distended with dark red blood
 Stomach & intestines
 Stomach may contain water
 In dead bodies, it is not possible for water to get beyond the cardiac sphincter &
into the stomach & intestine
Biochemical changes in blood
 In fresh water, haemodilution occur, viscosity of blood is decreased, it leads to
lyses of RBCs with liberation of potassium.
 Water entering lungs ,diffused in to pulmonary circulation and passing to left side
of heart.
 The chloride content of the left side of heart decreased.
 In salt water drowning ,all above changes are reversed.

20.  There is heamoconcentration ,viscosity of blood is increased , RBC ‘s are crenated
and chloride content of heart is increased.
 Gettler`s test
 Gettler devised test to estimate chloride content of blood from both sides of
heart.
 Blood is withdrawn from each ventricle of heart.
 The chloride content of blood is then analyzed.
 Normal chloride content in each chamber is 600mg/100ml.
 A difference of 25mg/100 ml is significant for drowning.
Diatoms test
 Diatoms: Microscopic unicellular algae, having a siliceous cell wall, resist acid,
heat and putrefaction.
 Only live body with a circulation can transport diatoms.
 Sample of material obtained from femoral or sternal bone marrow.
MEDICOLEGAL ASPECTS.
 Whether death was due to drowning.
 Manner is homicidal, suicidal, or accidental.
 Time since death from drowning.
Whether death was due to drowning
 Persistent, perfuse, fine froth at mouth and nose.
 Material grasped in hands.
 Fine typical froth in air passages.
 Edematous conditions of lungs.
 Diatoms in tissues specially brain and bone marrow.
 Gettler`s test

21. SUICIDAL, HOMICIDAL OR ACCIDENTAL
 SUICIDE
 Fairly common in women.
 May take her child with her.
 Attach wait to her body.
 May take poison, cut her throat.
Homicidal drowning
 Rare except in infants and children, stupefied and overpowered adults.
 Injuries may be found on the body.
Accidental drowning
 Very common.
 Injuries may be sustained during accidental fall.
Time since death from drowning
 A water proof wrist watch.
 Cooling rate is twice as compared to air.
 Rigor mortis sets early.
 Wrinkling of skin.
 Bleaching of cuticle.
 Sodden appearance of epidermis.
 Floating of the body.
 Body infected with flees and lices.
 Putrefactive changes.
 Skin of the hands and feet loose and peels like gloves and stocking.
Absence of signs

22.  Death due to shock or laryngeal spasm.
 First killed and then thrown in water.
 Minimal signs in submersion of unconscious.
Injuries
 Could be suicidal, homicidal or accidental.
 May sustained while falling.
 May be caused by water animals or by passing boats.