Mechanical Asphyxia

Question 1

Asphyxia definition

Answer 1

Exclusion of air from lungs

Question 2

Hypoxia definition

Answer 2

Inadequade supply of O2 at tissue level.

Question 3

Anoxia definition

Answer 3

Complete absence of O2 at tissue level

Question 4

Types of anoxia

Answer 4

Anoxiac
Stagnant
Histotoxic
Anaemic

Question 5

Classification of hanging

Answer 5

Degree of suspension
Complete
Partial

Position of knot
Typical
Atypical

Manner of hanging
Suicidal
Homicidal
Accidental
Judicial

Relation to death
Antemortem
Postmortem

Question 6

Classification of strangulation ( love makes girls pretty and boys muscular)

Answer 6

Ligature
Manual strangulation / throttling
Garotting
Palmer
Bansdola
Mugging

Question 7

Classification of suffocation (smart girls crack the wonderful personalities in boys)

Answer 7

Smothering
Gagging
Choking
Traumatic asphyxia
Wedging
Positional asphyxia
Overlaying
Burking

Question 8

Classification of drowning

Answer 8

Typical (wet)
Freshwater
Seawater

Atypical (dry)
Immersion syndrome (hydrocution)
Near drowning
Secondary drowning
Shallow water drowning

Question 9

Types of knot in hanging

Answer 9

Slipknot
Fixed / granny knot

Question 10

Sites of knot around neck in hanging

Answer 10

Occiput
Mastoid /mandibular angle
Below chin

Question 11

Types of noose in hanging

Answer 11

Running noose
Fixed noose

Question 12

Cuases of immediate death after hanging

Answer 12

Asphyxia (trachea occlusion)
Venous congestion (obstruction of jugular vein)
Cerebral ischaemia (occlusion of blood vessels of neck)
Reflex vagal inhibition of heart (pressure on carotid bodies)
Fracture dislocation of cervical vertebrae (judicial hanging)

Question 13

Causes of delayed death in hanging

Answer 13

Aspiration pneumonia
Pulmonary oedema
Infection and septicaemia
Hypoxic encephalopathy
Brain abscess
Laryngeal oedema

Question 14

Autoerotic asphyxia (sexual asphyxia)

Answer 14

Partial asphyxia by means to enhance sexual arousal.
Hanging
Suffocation (plastic bags)
Manual pressure ( carotid vessels)
Accidental( not suicidal)

Question 15

Signs of homicidal throttling

Answer 15

Multiple number of bruises
Fingernail marks
Victims : weak individuals
More marked on young + healthy
Present on both accused and victim

Question 16

Example of combination of amothering and strangulation

Answer 16

Palmer strangulation

Question 17

Bansdola

Answer 17

Neck complessed between two bamboos

Question 18

Mugging

Answer 18

Holding neck of the victim in bend of the elbow from behind.

Question 19

Types of smothering

Answer 19

Accidental
Homicidal
Suicidal (rare) (mentally retarded)

Question 20

Classification of Drowning

Answer 20

Wet drowning
Dry drowning
Immersion syndrome (hydrocution)
Near drowning (<24 hr)
Secondary drowning (>24 hr)
Shallow water drowning

Question 21

Lynching

Answer 21

Type of homicidal killing
Hanging without legal trial

Lynch’s law

Question 22

Cause of death in lynching

Answer 22

Asphyxia (hanged)

Question 23

Cafe coronary

Answer 23

Sudden death due to obstruction of upper airways by bolus of food.
By Dr. Roger Haugen

Question 24

Mechanism of death by cafe coronary

Answer 24

Large bolus stimulates recurrent laryngeal nerve leading to cardiac arrest.
Large bolus stimulates vagus nerve to dilate esophagus causing bronchospasm + bradycardia leading cardiac arrest.

Question 25

Cause of death by cafe coronary

Answer 25

Reflex vagal inhibition of heart

Question 26

Postmortem findings in cafe coronary

Answer 26

Large bolus at entrance of larynx Signs of choking/asphyxia occur first then death occurs by vagal inhibition

Question 27

External postmortem findings in traumatic asphyxia

Answer 27

External Clear line of demarcation Above level of compression (retrograde displacement of blood from SVC into subclavian vein, face + lips + scalp swollen, cyanosis + congestion + purple decoloration on body, ears + eyes bleed) Below level of compression (pale /mildly cyanosed)

Question 28

Internal postmortem findings in traumatic asphyxia

Answer 28

Fractures of ribs,sternum,vertebrae. Brain congestion. Distended right side of heart. Contusions /lacerations on lungs and heart.

Question 29

Causes of wet drowning

Answer 29

Asphyxia Head injury Exhaution Hypothermia Ventricular fibrillation Apoplexy

Question 30

Types of wet drowning

Answer 30

Fresh water Sea water

Question 31

Mechanism of fresh water drowning Fatal period : 4min

Answer 31

Hypervolaemia Haemodilution Hyperkalemia Hyponatremia Hypoxiaemia Metabolic acidosis causing ventricular fibrillation leads death.

Question 32

Mechanism of sea water drowning Fatal period : 8-12min

Answer 32

Hypovolaemia Hypernatraemia Hypoxaemia leading to heart failure causing death.

Question 33

Characteristics of froth in fresh water drowning

Answer 33

Fine White Leathery Tenacious Reappears on chest commpression Sometimes blood stained Bubbles don't readily collapse

Question 34

Cutis anserina / goose skin / goose flesh

Answer 34

Skin is granular + puckered Usually in Wet drowning (cold water) Antemortem Due to contraction of erector pilorum muscle. Postmortem Dead body in water while muscles still irritable (rigor mortis / erector pilorum contraction)

Question 35

Washerman's hands and feet

Answer 35

Skin is bleached Sodden Thickened Wrinkled A sign of immersion (not antemortem drowning) (seen early in warm water)

Question 36

Events in Washerman's hand and feet

Answer 36

2-4 h: wrinkling+sodding of fingertips 4-8 h: bleching of epidermis 24 h: wrinkling+sodding+bleaching (hand) 48 h: peeling of cuticle (palm+sole) 3-4 days: skin peeled like glove

Question 37

External features of wet drowning

Answer 37

Face Froth Cutis anserina /goose skin / goose flesh Washerman's hand and feet Cadaveric spasm Rigor mortis / putrefaction Hypostasis

Question 38

Internal features of wet drowning

Answer 38

Trachae+bronchi full of froth+water Congested / pale lungs Paltauf's haemorhhage Emphysema aquosum+oedema aquosum (characteristic) Hydrostatic lung (wothout froth) Right side of heart dilated Water (stomach+middle ear,paranasal sinus) Oedematous brain Blood in fluid Spleen size+weight decresed All Organs are congested

Question 39

Paltauf's haemorhhage

Answer 39

Haemorhhage die to rupture of alveolar walls Subpleural haemorhhages in lungs Multiple Shining pale pink /bluish rush 3-5 cm in diameter Commonly in lower lobe /interlobular surfaces /ant. Surface of lungs

Question 40

Effect of fresh water drowning on RBCs

Answer 40

Water enters the RBC by osmosis RBC swells Burst - Haemolysis Haemoglobinemia Haemoglobinuria Hyperkalemia Hyponatraemia

Question 41

Effect of freshwater drowning on lungs

Answer 41

Denatures protective surfactant leading to pulmonary oedema