3. strangulation
• Strangulation is a form of asphyxia
• characterized by closure of the blood vessels
and air passages of the neck due to external
pressure on the neck.
4. Hanging (suicidal)
• In hanging, asphyxia happen due to
compression /constriction of the neck by a
noose or other constricting band tightened
with weight of the body.
• In hanging, the cause of death is cerebral
hypoxia secondary to compression and,
thereby, occlusion of the vessels supplying
blood to the brain.
5. 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)
(DiMaio2001)
6. Type Of Hanging
• There may be either complete or incomplete
suspension of the body
8. • the face is pale and the tongue is protruding
• Absence of petechiae in
most hangings is because
there is complete
obstruction of the arterial
system, so there is no
pooling of blood in the
head, no increased
pressure, and, therefore,
no petechiae
9. Material used
• Most common are ropes, electrical cords, and
belts. In jails and prisons, convicts typically
tear sheets into strips as well as using T-shirts,
undershorts, trousers, or even socks.
• Usually, to prevent a change of mind, the
victim ties his hands together.
10. Figure 8.14
Hanging with point of suspension on (A) side of
neck and (B) front
of neck
• The most common
point of suspension is
the side of the neck,
• followed by the back
and the front. (Figure
8.14)
Point of suspension
11. • At the time of
suspension, the noose
typically slips above the
larynx, catching under
the chin (Figure 8.15)
Figure 8.15
Furrow from noose slanting upward toward point
of suspension.
12. The Furrow
• Present on the neck
will be a furrow. This
furrow generally does
not completely
encircle the neck,but
rather slants upward
toward the knot,
fading out at the
point of suspension
(the knot) (Figure 8.16).
Figure 8.16
(A) Noose mark with pale yellow base and
congested rim.
13. • To clarify of the furrow, depend on the
material used. A rope will give deep, well-
demarcated, distinct furrow, often with a
mirror-image impression of the twist of the
rope on the skin
• If the ligature is a soft
material, the groove
might be poorly
defined, pale, and
devoid of bruises and
abrasions(Figure 8.16a).
Figure 8.16
(A) Noose mark with pale yellow base and
congested rim. (B) Broad
pale furrow due to soft noose.
14. • In hangings, blood will pool in the dependent
areas of the body, usually the forearms,
hands, and lower legs, secondary to gravity.
• This is caused by hydrostatic rupture of vessels
16. Suffocation
• Major Form in Asphyxia
• Def: Suffocation is a general term used to
indicate death due to lack of oxygen, either
from lack of the gas in the breathable
environment or from obstruction of the
external air passages.
• Asphyxia = lack of oxygen in respired air
causing hypoxaemia and hypercapnia
17. Smothering
• Asphyxia by smothering is caused by the
mechanical obstruction or blocking of the
external airways, (nose and mouth)
• Deaths such as these are usually either
homicide or suicide,
18. Suicidal smothering
• suicide eg head covered in plastic bag
• Mechanism: hood of impervious
substance, usually polythene or other
plastic, is placed over the head down to
neck level.
• The plastic is usually in the form of an
open-ended bag, either transparent or a
‘supermarket’ shopping bag
(DiMaio2001)
19. • Figure 4.7
Plastic bag
suicide, with an
open bag placed
loosely over the
head.
20. • Figure 8.l
• (A) Suicide of elderly
female who secured
plastic bag over head
withtie around neck.
Cont.
21. • Figure 14.6 Plastic bag suicide. The bag is
sometimes tied around the neck,
23. • Petechiae are caused by an acute rise in
venous pressure causing overdistension and
rupture of thin walled peripheral venules,
• especially in lax tissues(eyelid), &
unsupported serous membranes (pleura and
epicardium)
24. Cont.
• Petechiae of the epicardium or pleural
surfaces of the lung were sometimes present,
but these are so nonspecific
• Petechiae of the face, sclerae, and
conjunctivae were virtually always absent.
-Knight F.
25. • Cynosis: The colour of blood depends on
quantity of oxyhaemoglobin
• When oxygen is lacking (cyanosis), normal
pink colour of well-oxygenated skin may
change to purple/ blue
• The Congestion & oedema is due to reduce
venous return, result of rapid transudation
thru capillary and venule walls,
-Knight F.
28. Pattern of injury of
vehicle occupants
• The pathology of all these is no different from
accidents elsewhere (Knight f. p293)
• The type of vehicle (theory) makes little
difference to the mechanism of injury
• In crashes, Heavy goods vehicles naturally
suffer less than light vehicle because of their
far greater mass and strength
-Knight F.
29. Cause of death
• gross musculoskeletal or organ damage,
• severe haemorrhage,
• blockage of air passages from blood, or
• traumatic asphyxia from fixation of the chest
caused by crushing from some part of a
vehicle.
-Knight F.
30. railway injury (suicidal)
• The common railway fatality is the suicide
who lays himself in front of an approaching
train.
31. • The Ix for alcohol and other drugs must be
made, as suicides often employ multiple
methods to ensure self-destruction.
• Sometimes the injuries complicated by high-
voltage electrical lesions, as the typical
traction voltage of an electric railway is in
excess of 600 volts.
32. • Decapitation is the most common injury
• Other obvious features are the local tissue
destruction, usually with grease, rust or other
dirt soiling of the damaged area
33. • Figure 9.27 Amputation of the right arm and
bruising of the face and chest in a pedestrian
struck by a passing locomotive
34. • Figure 9.28 Extensive disintegration of the
body that has been run over by a train.
37. ELECTROCUTION
• most deaths from electricity are from cardiac
arrhythmias, usually ventricular fibrillation
ending in arrest
• second (and far less common) mode of death
is respiratory arrest, in which the passage of
current through the thorax causes the
intercostal muscles and diaphragm to go into
spasm, or become paralysed
42. • occurrence of an areola of blanched skin at
the periphery
• When voltage is in the multi-kilovolt range,
sparking may occur over many centimetres.
This can give multiple burn lesions giving rise
to a ‘crocodile-skin’ effect
CHARACTERISTICS
43. • Charring and more extensive peeling and
blistering of skin may occur, with deep muscle
damage and cooking of the tissues when the
current has flowed for an appreciable time
44. INTERNAL APPEARANCES
• gross findings in the internal organs may be
absent and even histological changes are a
matter of controversy
• usual mode of death is cardiac arrhythmia
leading to ventricular fibrillation and arrest –
little to no evidence during autopsy (epicardial
petechiae may occur, but these are too non-
specific to be of any use)