Asphyxia refers to a condition where cells or organs do not receive enough oxygen. It can be partial (hypoxia) or total (anoxia). There are four main types of anoxia: anoxic, stagnant, anaemic, and histotoxic. Hanging, strangulation, and drowning are three common forms of violent asphyxia that can cause death. In a hanging, the weight of the body constricts the neck, while in strangulation an object other than the body applies pressure. Drowning occurs when fluid prevents air from entering the lungs. Autopsies of asphyxia victims examine for signs like petechial hemorrhages, visceral congestion, and

1. ASPHYXIA
Dept. of Forensic Medicine
NEIAH,Shillong

2. Definition
❏ Term “asphyxia” mean “lack of oxygen”
❏ Etymologically the word means “absence of pulsation”
❏ A condition where the cells or organs do not receive oxygen.
The condition can be partial (hypoxia) or total (anoxia).

3. Anoxia
❖ Characterised by failure of O2 to reach the cells
❖ Four types-
a)Anoxic Anoxia:Due to reduced availability of O2 in the alveoli for inspiration
b)Stagnant Anoxia;Results from slowing of circulation,causing imperfect
oxygenation in presence of available O2
c)Anaemic Anoxia:Results from decreased O2 carrying capacity of the blood
d)Histotoxic Anoxia:Because of conditions interfering utilisation of O2 by cells
inspite of available O2 in cellular level

4. Violant Asphyxia
❏ In violant Asphyxia also called mechanical asphyxia,the process of
respiration i.e. exchange of air between atmosphere and the lung beds is
prevented by some mechanical means
❏ Can be caused by
● Constriction of the neck.
● Closure of mouth and nose
● Occlusion of the lumen of air passage by some material
● Restricting the movement of respiratory muscle
● Suffocation

6. THE CLASSIC SIGNS OF ASPHYXIA
1. CYANOSIS
2. PETECHIAE HAEMORRHAGES
3. VISCERAL CONGESTION
4. FLUIDITY OF BLOOD

7. PETECHIAE HEMORRHAGES
❖ Pinpoint hemorrhages produced by ruptured of
small vessels, predominantly small venules.
❖ Size from a tent of millimetre to about two
millimetre.
❖ Rupture is caused by sudden over distention or
increases in intravascular pressure.
❖ It is classically seen in the conjunctivae and
sclerae (strangulation).
❖ It often known as ’tardieu spot’

8. Symptoms and signs of asphyxia
Can be described under three phases
❖ Dyspnoeic Phase
❖ Convulsive phase
❖ Apnoeic Phase
❖ Paralysis

9. Hanging
Hanging is a form of asphyxial death due to constriction of the air passage at the
neck,as a result of suspension of the body by a ligature in the form of a noose
,applied in such a manner ,when the weight of the body or part of the body acts
as a constricting force
Typical hanging-Here vessels of the neck completely occluded to the maximum
as point of suspension is over the occiput

10. Complete hanging-Body remains
completely suspended,no body
parts is in touch with the
ground. Constricting force is
weight of the body.
Partial Hanging- Here some
body parts are in touch with the
ground,constricing force weight
of the head not the body

11. Amount of pressure needed
The amount of pressure necessary to compress
• the jugular veins is 4.4 lb (2kg)
• the carotid arteries, 11 lb(5kg)
• the vertebral arteries, 66 lb (33kg)
• Compression of the trachea requires 33 lb (15kg)

12. Symptoms of Hanging
❏ Loss of power and the subjective sensations, such as flashes of light
and ringing and hissing noises in the ears.
❏ These are followed by loss of consciousness, which is
so rapid that hanging is regarded as a painless form of death
❏ In the case of judicial hanging, convulsive movements of the limbs
caused by anoxia may be seen.
❏ Respiration stops before the heart, which may continue to beat for about
10 to 15 minutes

13. Mode of death
1)Asphyxia
2)Apoplexy or congestive Suboxia or Venous congestion
3)Syncope or Cerebral Ischemia
4)Vagal inhibition
5)Fracture dislocation of cervical vertebrae
6)combine affects

14. Delayed Death
Death delayed for several days is rare. Delayed deaths occur due to
1)Aspiration Pneumonia
2)Infection
3)Lung edema
4)Hypoxic Encephalopathy
5)Infarction of brain
6)Brain abscess

15. Fatal Period
Death occurs immediately if the cervical vertebrae are fractured, or if the heart
is inhibited; rapidly if cause is asphyxia, and least rapidly if coma is
responsible. The usual period is 3 to 5 minutes

16. Post-mortem Appearances(External)
The ligature mark in the neck is the most important and specific sign of death
from hanging. Ligature mark on the neck depends on
❖ Composition of ligature
❖ Width and multiplicity of ligature
❖ The weight of the body suspended and the degree f the suspension
❖ The tightness of encircling ligature
❖ The length of time body has been suspended
❖ Position of the knot
❖ Slipping of ligature during suspension

17. KNOT
❏ Knot is frequently in the form of a simple slip-knot to produce a
running noose or fixed by granny or reef-knot; occasionally a
simple loop is used.
❏ The knot is usually on the right or left side of the neck, ligature
usually rising behind the ear to the point of suspension.
❏ Sometimes, the knot is in the occipital region and rarely under
the chin.
❏ After suspension in hanging, the knot is at higher level than the
remainder of ligature, the movement of knot being due to the act
of suspension

18. Ligature Mark:
❏ The ligature produces a furrow or groove in the tissue which is pale in color,
but it later becomes yellowish or brownish yellow and hard like parchment,
due to the drying of the slightly abraded skin.
❏ The course of the groove depends on whether a fixed or running noose has
been used, when the loop is arranged with a fixed knot, the curse of the mark
is deepest and nearly horizontal on the side opposite to knot, but as the arms
of the ligature approach the knot the mark turns upwards towards it.
❏ Hanging from a high suspension point leaves diagonal marks on the neck
like an inverted V, which does not run around the full circumference of the
neck.

20. 1.Facies-Appearances may vary according to mode of death.May be pale flacid or
may congested with tiny patechial spots over forehead,neck ..
2.Cyanosis-Deep cyanosis is noticed
3.Eyes-May be closed or partly open or may be protruding with suffused
conjuntiva.Patechial spots may be noticed
La Facies Sympathique
4.Tongue-The tongue may remain within the teeth or between the teeth bitten.It
may get swollen,blue and dry

21. External findings
Saliva-Saliva will be found to trickle down from the lower angle of mouth ,down
the chin on the chest in straight lines. The secretion of saliva is vital indication of
suspension during life
Post mortem Staining-Will be well marked in the dependent parts of the body
with gloves and stocking like distribution in both hand,lower parts of both
forearms and legs.

22. Internal Findings
❏ Superficial incision of the groove may show small hemorrhages in the underlying
layers of skin, caused by the direct trauma produced by the ligature.
❏ The tissues under the mark are dry, white and glistening with occasional
ecchymosed in the adjacent muscles.
❏ In most cases, there is no bruising of strap muscles or other soft tissues, the muscles
of the neck, especially the platysma and sternomastoid are ruptured (5 to 10%), if
violence has been considerable.
❏ In some cases (5 to 10%), the intimae of the carotid arteries show transverse splits
with extravasations of blood in their wall due to stretching and crushing.

23. ❏ Opinion varies regarding the frequency of fracture of the hyoid bone.
Estimates range from 0 to 60%, but the average is 15 to 20%. Fractures
are rare below 40 years because of the elasticity of the cartilage and
mobility of the joint
❏ The fracture is common in persons above 40 years and involves the
great horns, at the junction of inner two-thirds and outer one-third.
❏ The superior horns of the thyroid may be fractured from pressure on
the thyroid ligament in about 40% of cases above 40 years.

24. ❏ Injury to the trachea is unusal. Petechial hemorrhages may be found
on the epiglottis, in the larynx and trachea. The trachea is usually
congested.
❏ The lungs are congested, oedematous, and exude bloody serum on
section in cases of constriction occurring at the end of expiration; but
they are pale if constriction occurred at the end of inspiration.
❏ The abdominal organs are usually congested.
❏ The brain is usually normal, but may be pale or congested according to
the mode of the death. Subarachnoid effusions are common

27. Diagnosis
a.Ligature mark around the neck
b.Presence of abrasions, ecchymoses and redness about the ligature
mark,
c.Trickling of saliva from the mouth,
d.Ecchymoses of the larynx or epiglottis,
e.Rupture of the intima of the carotid, and
f.Post-mortem signs of asphyxia.

29. Antemortem hanging vs Postmortem Hanging
Ligature mark
features
Produces prominent furrow or groove
in the tissues, which becomes
yellow or brown, and parchment-like
No characteristic
Salivary dribble Present. Sometimes dried saliva
stains be present over the front of
chest
Absent
La Facies Sympathique May be present Absent
Drag marks on the body Absent May be present
Rope fibres May be present in the victim of the hand Absent
Genearal Asphyxial signs Present Absent

30. STRANGULATION
Def.-It is a form of asphyxial death caused by constriction of the neck by means
of a ligature or any means other than suspension of the body.
Unlike hanging weight of the whole body or part of it is not the constricting
force.

31. Means to cause strangulation
a) By a ligature- Ligature strangulation
b) By hand -Manual strangulation or throttling
c) By compressing the throat the throat with foot,knee,elbow or such some
other solid substances
d) By use of rods,lathis,sticks,bamboo--Bansdola
e) Mugging-Is a form of strangulation that can be effected by holding the neck
of the victim in the bend elbow or knee of the assailant
f) Palmer strangulation
g) Garroting

32. CAUSES OF DEATH
a) Asphyxia
b) Asphyxia and apoplexy
c) Vagal inhibition
d) Rarely fracture dislocation of cervical vertebrae

33. MANUAL STRANGULATION (THROTTLING)
❏ When hands are used to squeeze or compress
the neck.
❏ It is always homicidal. At times however, a mild playful tweak on the neck has
resulted in death from vagal inhibition.
AUTOPSY FINDINGS:
❏ Signs of asphyxia are seen.In addition, the following specific findings may be
present:
❏ Brusing of the neck:
❖ Occurs due to the assailant’s fingers grasping the neck.
❖ Usually circular, dark red or purple in colour, and are 1-2cm in size.
❖ If the fingers slide over the skin, elongated marks may be seen.

34. ❏ Abrasions on the neck:
❖ Scratches maybe caused by the fingernails of either the assailant or the victim.
❖ Curved or linear.
❖ During autopsy, scrapings from under the fingernails of the deceased maybe taken
for DNA fingerprinting and compared with that of the suspect, because the victim
may have scratched the assailant in an attempt to ward off the attack.
❏ INTERNAL APPEARANCES:
❖ Tissues of the neck are often markedly contused.
❖ Bleeding maybe seens in the strap muscles or platysma.
❖ If excessive force has been applied, bleeding from larynx may have occurred.
❖ Hyoid bone fracture is quite common
❖ Fracture of thyroid cartilage may present

36. Ligature strangulation
❏ Materials used for ligature strangulation can be anything from flexible rubber tubing
to cloth, or stick, wooden planks, belts, wire, rope etc.
❏ Usually wound transversely around the neck, sometimes with several turns and is
often below the level of the thyroid cartilage.
❏ Intense congestion of the face, bleeding from nose, mouth and even ears are
characteristic features.
❏ Involuntary passage of urine, defecation etc. are more common.
❏ In infants, homicidal strangulation maybe brought about by winding the umbilical
cord around the neck.

37. AUTOPSY FINDINGS OF LIGATURE STRANGULATION:
 Classical and non-specific signs of asphyxia are prominent.
 Tongue is often protruded.
 Bleeding from the ears or the nose maybe seen.
 The ligature mark is seen as a depression around the neck because of oedema of the
tissues above and below it. The skin over the mark is dry and hard. The base appears
pale, while the edges show small abrasions. The width of the mark depends on the
ligature used. The pattern of the ligature may get imprinted on the skin as imprint
abrasion.

38.  The ligature mark completely encircles the neck in strangulation, while in hanging it is absent
near the point of suspension.
 The occurrence of a narrow zone of engorgement or bruising immediately above and below
the groove, confirms that the victim was alive at the time when the ligature was applied.
 Even if putrefaction has set in, the ligature mark usually remains distinct.
 Asphyxial component is always more pronounced in strangulation, as compared to hanging.
 Carotid arteries often show transverse intimal tears.
 Fracture of left or right superior horn of thyroid cartilage is a common feature. If more force is
applied, there may also be fracture of cricoid cartilage and tracheal rings.

41. DROWING
DEFINITION-It is a form of asphyxia death where air entry into lung is prevented
due to submersion of mouth and nostrils in to water or any fluid medium
Complete submersion o the body is not necessary
Drowing can be-1)Wet drowing
2)Dry Drowning
3)Secondary drowning
4)Immersion syndrome
5)Shallow water drowning