الرحيم الرحمن الله الرحيم بسم الرحمن الله بسم

ASPHYXIAASPHYXIA

DefinitionDefinition::

Conditions in which the supply of oxygen Conditions in which the supply of oxygen to the blood and tissues has been to the blood and tissues has been reduced below the normal working level reduced below the normal working level by any interference with respiration. by any interference with respiration.

Asphyxia is used as being equal to “lack Asphyxia is used as being equal to “lack of oxygen” or “hypoxia”, of oxygen” or “hypoxia”,

Gordon’s classificationGordon’s classification:: Anoxia is classified into 4 types:Anoxia is classified into 4 types:I) Anoxic anoxia:I) Anoxic anoxia:This means defective oxygenation of This means defective oxygenation of

blood in the lung and due to:blood in the lung and due to:1- Absence of oxygen1- Absence of oxygen . .2- Obstruction to respiratory passage 2- Obstruction to respiratory passage 3- Obstruction to respiratory movements 3- Obstruction to respiratory movements 4- Depression of respiratory centre4- Depression of respiratory centre

II) Anemic anoxia O2 carrying capacity of the blood: hemorrhage O2 carrying capacity of the blood: hemorrhage

and CO poisoningand CO poisoningIII) Stagnant anoxia: Inefficient circulation through the tissues, as in: Inefficient circulation through the tissues, as in:

Shock and heart failureShock and heart failure

IV) Histotoxic anoxia:Inability of the tissues to utilize oxygen delivered to Inability of the tissues to utilize oxygen delivered to

them, cyanide poisonthem, cyanide poison

Stages of asphyxiaStages of asphyxia1- Stage of dyspnea:1- Stage of dyspnea:Cyanosis, rapid deep breathing with acting

extraordinary muscles of respiration. Rapid pulse and high blood pressure.

2- Stage of convulsions:2- Stage of convulsions: Cyanosis becomes deeper. Breathing

becomes difficult and spasmodic. Congestion and edema of lungs and other organs. Petechial hemorrhages in skin, lungs, heart and brain. Convulsions occur.

33 - -Stage of apnea (respiratory paralysis)Stage of apnea (respiratory paralysis)::

Unconsciousness occurs. Breathing Unconsciousness occurs. Breathing becomesbecomes

shallow,shallow, infrequent and infrequent and gasping,gasping, then apnea occurs.then apnea occurs. Pulse becomes weak and BP is Pulse becomes weak and BP is

reduced.reduced.

External Postmortem (PM) picture

1- Petechial hemorrhages:1- Petechial hemorrhages: Sites of formation: Mechanism of formation2- Postmortem hypostasis is well-

developed and dark in color 3- Cyanosis4- Rigor mortis is rapid5- Putrefaction is rapid.

Internal Postmortem (PM) picture

Petechial hemorrhages under the pleura Petechial hemorrhages under the pleura and pericardium and in the internal and pericardium and in the internal organs. Congestion and edema of the organs. Congestion and edema of the viscera ( except the spleen).viscera ( except the spleen).

The blood is dark in color and more fluidly.The blood is dark in color and more fluidly. The right heart and great veins are The right heart and great veins are

engorged with blood.engorged with blood.

Violent Asphyxial DeathsViolent Asphyxial Deaths

1- Hanging

2- Ligature strangulation

3- Manual strangulation (Throttling)

4- Smothering:

5- Choking

6- Traumatic asphyxia (Crush asphyxia)

11 - -HangingHanging

It is Asphyxial death caused by It is Asphyxial death caused by suspension of the body by a ligature suspension of the body by a ligature around the neck, the constricting force around the neck, the constricting force being the weight of the body.being the weight of the body.

A) It may be either complete or partial:A) It may be either complete or partial:

B) It may be either typical or atypical:B) It may be either typical or atypical:

Mechanism of deathMechanism of death::

1.1. Cerebral anoxiaCerebral anoxia

2.2. Cerebral congestion.Cerebral congestion.

3.3. Asphyxia: Asphyxia:

4.4. Reflex vagal inhibitionReflex vagal inhibition

ExternallyExternally::

The neck is stretchedThe neck is stretched. . The face is pale or bluishThe face is pale or bluish.. The rest of the body is cyanosed. The rest of the body is cyanosed. Saliva may be seen dripping from the mouthSaliva may be seen dripping from the mouth

((It is a vital sign and is present only in hanging It is a vital sign and is present only in hanging but not in postmortem suspension).but not in postmortem suspension).

Ligature markLigature mark::

Shape:Shape:It is a depression at the site of the ligatureIt is a depression at the site of the ligature Situation: Situation: Transverse and completeTransverse and complete (if running noose).(if running noose). The pattern of the ligature:The pattern of the ligature:Is imprinted on the neck as a pressure Is imprinted on the neck as a pressure

abrasion.abrasion.

InternallyInternally::

Fracture of the hyoid boneFracture of the hyoid bone Petechial hemorrhage and ecchymosis of Petechial hemorrhage and ecchymosis of

the subcutaneous tissue under the the subcutaneous tissue under the ligature, but never in postmortem ligature, but never in postmortem suspension.suspension.

Is it hanging or PM suspension?Is it hanging or PM suspension?

Is it suicidal, homicidal, Is it suicidal, homicidal, or accidental hangingor accidental hanging??

Suicidal: (most common):Suicidal: (most common): Circumstantial evidence (history of failure).Circumstantial evidence (history of failure). Absence of signs of struggle.Absence of signs of struggle. Presence of signs of previous suicidal Presence of signs of previous suicidal

attempts.attempts. Suicidal noteSuicidal note

22 - -Ligature strangulationLigature strangulation

A violent Asphyxial death caused by A violent Asphyxial death caused by constricting the neck by a ligature.constricting the neck by a ligature.

Mechanism of death:Mechanism of death: Asphyxia: from compression of air passageAsphyxia: from compression of air passage Cerebral congestion or apoplexy:Cerebral congestion or apoplexy: Reflex vagal inhibitionReflex vagal inhibition Cerebral anoxia:Cerebral anoxia: Combination of any of the aboveCombination of any of the above

Autopsy appearancesAutopsy appearances::

Externally:Externally: The face is either pale or bluish and The face is either pale or bluish and

congested. The rest of the body is congested. The rest of the body is cyanosed.cyanosed.

The tongue may be protruded, swollen The tongue may be protruded, swollen and bitten.and bitten.

Bleeding from ears and nose may be Bleeding from ears and nose may be seen.seen.

Ligature markLigature mark::

Shape: as in hanging.Shape: as in hanging. Situation: At the level of thyroid cartilage Situation: At the level of thyroid cartilage

or below.or below. Symmetrical Symmetrical Transverse and Transverse and complete (this is the usual).complete (this is the usual).

Ligature markLigature mark::

A postmortem swelling of the neck A postmortem swelling of the neck associated with exaggeration of associated with exaggeration of

skin foldsskin folds or any or any clothes worn around the neckclothes worn around the neck

may produce depressed marks. All these may produce depressed marks. All these look like ligature mark. Neck dissection look like ligature mark. Neck dissection can differentiate can differentiate

Suicide, homicide, or Suicide, homicide, or accident:accident: Newborns strangled by the umbilical cord. Newborns strangled by the umbilical cord. Children plying with ropesChildren plying with ropes Adults strangled by the neck tie caught in Adults strangled by the neck tie caught in

moving machinery.moving machinery.

Methods commonly used for homicidal strangulation:

MuggingMugging: by compressing the victim's neck against : by compressing the victim's neck against the forearm.the forearm.

GarrotingGarroting: attacking the victim from behind and : attacking the victim from behind and grasping his throat or throwing a ligature over the grasping his throat or throwing a ligature over the neck and tightening it quickly.neck and tightening it quickly.

BansdolaBansdola: compressing the neck between 2 sticks : compressing the neck between 2 sticks ThrottlingThrottling: by compressing the victim's neck by the : by compressing the victim's neck by the

hand.hand.

Differences between hanging and

strangulation:: CircumstantialCircumstantial

Rope marksRope marks

Signs of resistance Signs of resistance

Starched neckStarched neck

33 - -Manual strangulation (Throttling)Manual strangulation (Throttling) caused by constricting the neck by the hand.caused by constricting the neck by the hand.

Mechanism of deathMechanism of death:: Autopsy appearances:Autopsy appearances:When death occurs as a result of vagal When death occurs as a result of vagal

inhibition, Asphyxial signs will be absent. inhibition, Asphyxial signs will be absent. Externally:Externally: Injuries on the neck:Injuries on the neck: Abrasions (caused by finger nails).Abrasions (caused by finger nails). Contusions (caused by finger pads).Contusions (caused by finger pads). Both are found on the front and sides of the Both are found on the front and sides of the

neckneck

Suicide, homicide, or accidentSuicide, homicide, or accident::

Suicide: A case was recorded and it Suicide: A case was recorded and it was due to cadaveric spasm.was due to cadaveric spasm.

Homicide: (most common)Homicide: (most common) Circumstantial evidence.Circumstantial evidence. Presence of signs of struggle.Presence of signs of struggle. Evidence of drink or drugs, or the Evidence of drink or drugs, or the

victim is young or weak.victim is young or weak.

44 - -SmotheringSmothering:: Caused by mechanical occlusion of the air Caused by mechanical occlusion of the air

passages from outside (i.e. the mouth and passages from outside (i.e. the mouth and nostril) by hand or by any object.nostril) by hand or by any object.

PM picturePM picture Asphyxial signs will be present except in case of Asphyxial signs will be present except in case of

plastic bag suffocation.plastic bag suffocation. Abrasions and contusions on the skin of the face Abrasions and contusions on the skin of the face

around mouth and nosearound mouth and nose

(Absent if a soft material, such as a pillow, is used).(Absent if a soft material, such as a pillow, is used).

Suicidal, homicidal, or Suicidal, homicidal, or accidentalaccidental::

SuicideSuicide By hand is impossible.By hand is impossible.

(Tying a plastic bag over the head is (Tying a plastic bag over the head is rare).rare).

Accident: (most common)Accident: (most common) In children playing with plastic bags.

An alcoholic adult who rolls over (during sleep) and his face in the pillow.

55 - -ChokingChoking

Caused by mechanical occlusion of the Caused by mechanical occlusion of the air passage from inside.air passage from inside.

Mechanism of death:Mechanism of death:

Asphyxia: due to either complete occlusion Asphyxia: due to either complete occlusion of air passage, or partial occlusion that is of air passage, or partial occlusion that is completed by spasm, edema and mucus completed by spasm, edema and mucus secretion.secretion.

Accidental: (most Accidental: (most common)common)

May arise from:May arise from: Inhalation of irritant fumes.Inhalation of irritant fumes. Impaction of foreign material, such as food or Impaction of foreign material, such as food or

denture.denture. Inhalation of dust and sand in falling of houses.Inhalation of dust and sand in falling of houses. Inhalation of vomit or blood during operations.Inhalation of vomit or blood during operations. Falling back of the tongue epileptic fit.Falling back of the tongue epileptic fit. Café coronary: Café coronary:

6 -Traumatic asphyxia (Crush asphyxia)

Resulting from trauma to the chest or pressure Resulting from trauma to the chest or pressure on the chest and abdomen which prevent on the chest and abdomen which prevent respiratory movementsrespiratory movements

*Penetrating trauma e.g. stab injury *Penetrating trauma e.g. stab injury pneumothorax pneumothorax lung collapse lung collapse

*Non-penetrating trauma e.g. run-over car *Non-penetrating trauma e.g. run-over car accident accident fracture of ribs fracture of ribs restriction of restriction of respiratory movements from the severe pain respiratory movements from the severe pain occurring during respiration.occurring during respiration.

Pressure on the chest and Pressure on the chest and abdomen due toabdomen due to::

Burial in earth following house collapse.Burial in earth following house collapse.

Crushing by a crowd, as in case of a fire.Crushing by a crowd, as in case of a fire.

77 - -Drowning (Immersion)Drowning (Immersion)::

It is a form of violent asphyxia in which It is a form of violent asphyxia in which death results from submersion of mouth death results from submersion of mouth and nostrils of a living person under and nostrils of a living person under

waterwater

Classification (types) of drowningClassification (types) of drowning::

1- Typical (wet) drowning: 1- Typical (wet) drowning:

2- Dry drowning.2- Dry drowning.

3- Secondary drowning (Near-3- Secondary drowning (Near-drowning).drowning).

Physiopathological changesPhysiopathological changes::

In fresh water In fresh water hypervolemia hypervolemia hypoxia and potassium excess.hypoxia and potassium excess.

In salt water In salt water pulmonary edema pulmonary edema hypovolemia and circulatory shock.hypovolemia and circulatory shock.

Dry drowningDry drowning::

Water in the larynx Water in the larynx laryngeal spasm laryngeal spasm asphyxiaasphyxia

Near-drowning (2nd drowning syndrome):

glistening pleural surface of a lung

PM picture of drowningPM picture of drowning::

These are signs of asphyxia unless These are signs of asphyxia unless death occurred from death occurred from

1- shock, 1- shock,

2- syncope,2- syncope,

3- concussion.3- concussion.

External appearancesExternal appearances

1.1. Signs of immersionSigns of immersion::These are found in any body found dead in These are found in any body found dead in

water (whatever the cause of death).water (whatever the cause of death). Coolness of the body.Coolness of the body. Goose-skin the skin is wrinkled.Goose-skin the skin is wrinkled. Washerwoman-skin: the skin is sodden.Washerwoman-skin: the skin is sodden. Peeling of the epidermis in the form of Peeling of the epidermis in the form of

gloves and stockings.gloves and stockings. HypostasisHypostasis

2- Sure external signs:2- Sure external signs:

A-Froth:A-Froth:(Fine – White – Odorless _ increase) (Fine – White – Odorless _ increase)

B-Cadaveric spasmB-Cadaveric spasm

of the hands on weeds, mud, sand, etc.of the hands on weeds, mud, sand, etc.

Internal appearancesInternal appearances

Voluminous lungs with indentation marks Voluminous lungs with indentation marks of ribs on their lateral surfaces. of ribs on their lateral surfaces.

Respiratory passages contain froth Respiratory passages contain froth (having the same characters of that (having the same characters of that found externally at the mouth and found externally at the mouth and nostrils),nostrils),

foreign material ( weeds, mud, sand,.).foreign material ( weeds, mud, sand,.).

A normal pink aerated appearance with minimal anthracotic

pigmentation ,

Diffuse alveolar damage in which the lung is diffusely firm and rubbery

DiatomsDiatoms::

These are microscopic, unicellular algae, These are microscopic, unicellular algae, found in fresh as well as salt water. found in fresh as well as salt water.

When a live person is drowned in water, When a live person is drowned in water, they penetrate his alveolar membrane and they penetrate his alveolar membrane and pass with the circulation to distant organs.pass with the circulation to distant organs.

But when a dead body is thrown into But when a dead body is thrown into water, the absence of beating heart water, the absence of beating heart prevents circulation of diatoms to distant prevents circulation of diatoms to distant organs.organs.

some of the plant material in the water was aspirated into a bronchus.

The medico-legal (ML) importance of The medico-legal (ML) importance of diatomsdiatoms::

1- Sure signs of drowning,1- Sure signs of drowning, 2- Could still be identified in putrefied 2- Could still be identified in putrefied

bodies,bodies, 3- Could give an evidence of the site of 3- Could give an evidence of the site of

drowning (fresh or salt water species).drowning (fresh or salt water species).

How to know that death was How to know that death was due to drowningdue to drowning::

1-Froth at mouth and nostrils: fine, white, 1-Froth at mouth and nostrils: fine, white, abundant.abundant.

2.Cadaveric spasm on weeds, mud or sand.2.Cadaveric spasm on weeds, mud or sand.

3.Lungs: voluminous, edematous with 3.Lungs: voluminous, edematous with indentation marks of the ribs.indentation marks of the ribs.

4.Froth in the air passages.4.Froth in the air passages.

5. Diatoms in the tissues.5. Diatoms in the tissues.

In putrefied bodiesIn putrefied bodies::

Only diatoms could be identifiedOnly diatoms could be identified