1. FORENSIC MEDICINE
&
TOXICOLOGY
PUNCTURED WOUNDS
Dr. Purnima Rani
iNTERN
NHMC & H-Delhi

2. ABSTRACT
The powerpoint presentation presented here gives all the information
regarding Punctured Wounds which are one of the important part of
Mechanical Injuries.
A general overview of the injuries, their mechanism and classification are
followed by detailed explanation of Punctured Wounds.
In the last part of presentation Medicolegal aspect of the same are also
included to make it useful for the readers from the forensic point of view.
Dr. Purnima Rani
Intern
NHMC

3. GENERAL CONSIDERATIONS
An overview of Mechanical Injuries
Injury-
An injury or wound means a disruption of the anatomical continuity of any of
the tissues of the body.
Under section 44 of IPC, an injury is defined as any harm whatever, illegally
caused to any person in body, mind, reputation, or property.
Mechanical Injuries-
Injuries caused by application of physical violence to the body are known as
mechanical injuries.

4. Mechanism of Injury
The main factors responsible for a mechanical injury are-
 Force- According to the laws of physics, force= ½mv2
, where m is the mass
and v is the velocity, the damage from the latter being much greater on
account of its being squared,. It means that a brick gently pressed against
the scalp will cause no injury but the same brick falling from a height on to
the head may smash the skull.
 Specific effect of the force- Blast effect (compression) from explosion
may do little harm to the muscle but may rupture the tympanic membrane,
lung, or intestine. A blow to the chest may bend the ribs without fracture
but may damage the thoracic viscera. A torsion force may leave the thigh fat
unaffected but cause a spiral fracture of the femur.

5. Mechanism of Injury
 Area over which it acts- The area over which the force acts is also important;
the damage to the tissues is much greater if the narrow edge of a plank is used to
strike the skin rather than the flat surface.
The resulting damage depends on
a) The effect of the force, e.g. compression, traction, torsion, tearing, etc.
b) The nature of the tissue involved, e.g. skin, muscle, lung, liver, brain, bone,
etc., and
c) The movement as a whole of the part that is struck. As for example, the skin
when struck with a blunt weapon often escapes injury though the underlying
tissues may be seriously damaged.

6. Mechanism of Injury
 Time taken over which the kinetic energy is transferred- In
firearm injuries, if a bullet exits, it means that it has not transferred all its
energy to produce the wounding effect. The function of seat belts in motor
vehicles is to lessen the effect of an impact in the event of a collision. This
is achieved by stretching of the belt fabric which slows down the impact
and spreads its effects over a wider area.

7. Classification of Mechanical Injuries
Depending on how they are caused, e.g. by blunt force, sharp
weapon, or firearm, they are classified as follows.
Abrasions (scratches, grazes, imprint or pressure marks)-
An abrasion is a superficial injury involving only the superficial
layers of the skin. It is caused by friction and/or pressure
between
the skin and some rough object or surface. It bleeds very
slightly,
heals rapidly in a few days, and leaves no scar.Bruises (contusions)- A bruise (contusion) signifies
haemorrhage into the skin, the subcutaneous tissues,
or deeper tissues. It is due to an infiltration or extravasations
of blood into the tissues, following rupture of small vessels,
as a result of application of blunt force, e.g. stick, stone, kick,
or fist. Usually, there is no loss of continuity of skin.

8. Classification of Mechanical Injuries
 Lacerations (splits, tears)- A laceration is a wound in
which the skin, mucosa, or underlying tissues are torn as a
result of application of blunt force.
Incised Wounds – An incised wound is an injury
caused by a weapon with a sharp cutting edge when it is
drawn across the skin. The injury varies in sharpness
according to the character of the weapon and the nature
of stroke made.

9. Classification of Mechanical Injuries
 Stab Wounds – A stab wound (punctured wound) is an
injury caused by a more or less pointed weapon when it is
driven in through the skin and its depth is the greatest
dimension.
Firearm Injury – Firearm injuries are wounds caused to
the body tissues due to impact, entry, and passage of a
missile discharged from a firearm. They generally simulate
contused wounds.

10. Classification of Mechanical Injuries
In medicolegal work, the following three technical terms based on
interpretation of the nature of injuries are commonly used irrespective of
the weapon causing them are:
 Defence Wounds
 Self-Inflicted Wounds
 Injury Patterns

12. Punctured Wounds
• Also known as Stab wounds.
• It is caused by pointed weapon when it is driven through the skin and its
depth is the greatest dimension
• Such weapons includes:
Knife
Dagger Needle
Spear ArrowScissorIce pick
ForkBayonet

13. Punctured Wounds
 Penetrating Wound: When the weapon enters a
body cavity such as the thorax or abdomen, the injury
is termed as penetrating wound.
 Perforating Wounds: When the weapon, after
penetrating the body tissues, comes out from the
other side making an exit wound, the injury is
termed as perforating wound (Transfixing Wound)

14. Description of a Punctured Wound
• It includes:
▫ Wound of entry - shape, size, margins, and presence of foreign bodies, if
any.
▫ Depth and direction
▫ Wound of exit, if present

15. Wound of Entry
The wound of entry is generally bigger than the wound of exit because the
stabbing weapon so often has a tapering tip. Clothes may be pushed into the
wound of entry.
• Shape: It may sometimes correspond to the blade of the weapon used.
Thus, it can be of following types:
1. Tear drop shaped 2. Wedge shaped 3. Spindle shaped
The occurrence of stab wounds in a paired pattern suggests the use of a
two pronged sharp weapon such as a fork, pair of scissors etc.

16. Wound of Entry
• During stabbing, there is often considerable relative movement between the
assailant and victim. The shape of the entry wound may therefore not
correspond to the weapon used. It may have an atypical appearance, e.g.,
triangular or cruciate, if the knife is twisted during withdrawl from the
tissues.
• Such atypical appearance may also result when the injury is caused by a
relatively blunt edged weapon, such as a bayonet, due to simultaneous
cutting and tearing of the skin during the process of stabbing.
• Repetition of a stab wound without complete withdrawl may “double” the
entry wound.
• Scrimmage enlargement is a term occasionally used to imply extension
of a wound due to motion of the weapon or body against the cutting edge.
• Wounds of internal viscera- shape in many cases is modified by the
muscular and elastic fibres in the capsule and framework of the organ.

17. Wound of Entry
• Size- The size does not necessarily correspond to the breadth or length of
the blade.
• The skin aperture is little smaller than the breadth of the weapon due to
elasticity of the skin.
• The knife may be pulled upwards or downwards during insertion or
withdrawl, thereby causing an injury which is broader than the widest part
of the blade.
• The least twisted or split entry wound is a guide to the maximum breadth of
the blade, provided the wound edges are apposed.

18. Wound of Entry
• Margins – the margins of the entry wound are clean
cut and the edges inverted.
• Some abrading and/or bruising of the edges may be seen due to the
thrusting force or if the weapon is not quite sharp, or if the weapon is
tapering and then becomes larger in cross section.
• When a weapon such as knife or dagger is thrust into
the tissues with considerable force, the skin
surrounding the wound may be abraded or bruised
by the hilt (guard) of the weapon. Such a condition
suggests that the blade has been completely inserted.

19. Wound of Entry
• Foreign body - when a punctured wound is produced by a fall on some
sharp object, such as a glass pot or sharp stones, the wound will have
bruised edges and a part of the foreign body may be found broken off the
wound.
• It is desirable to x-ray all stab wounds in search for a possible broken part
of a weapon or foreign body.

20. Depth and Direction
• The external examination of a stab wound gives no indication of its depth,
direction, or internal injuries. The most vital injury may be beneath a trivial
looking entry wound.
• The depth of a stab wound is greater than its length
and breadth.
• It does not depend on the length of the blade alone
but is also dependent on the thrusting force.
• It is generally not possible to measure the depth accurately due to the
presence of blood clots or injury to internal viscera.

21. Depth and Direction
• The direction of a stab wound can be ascertain by drawing a line joining
the wound of entry and wound of exit.
• This is helpful to determine the position of the victim and assailant.
• A single track is usually found in relation to a single entry wound but in
certain cases where the weapon is partially withdrawn and then inserted in
another direction , two or more tracks may be found in relation to a single
external opening.
• The depth and direction can be determined accurately only at autopsy by
meticulous dissection, in layers.

22. Wound of exit
• This is smaller if a tapering weapon is used and its edges are everted.

23. Cleavage lines of Langer

24. Cleavage lines of Langer
• These are lines of tension determined by the direction of the elastic and
collagenous fibres in the dermis of the skin.
• A cut which is inflicted across the natural lines of tension will tend to gape
while one which is inflicted parallel to these lines will remain slit shaped
and relatively undistorted.
• Restoration of a stab wound to its actual size usually shows the resulting
slit to be considerably longer than the oval shaped wound present on the
body. Such reconstruction should be a normal routine in the examination of
every stab wound.

25. Concealed puncture wounds
• Puncture wounds made by pins and needles, especially on concealed parts
of the body, may not be obvious. They are therefore sometimes known as
concealed puncture wounds.
• Commonly found in such parts of the body as fontanelle, inner canthus of
the eye, up the nostrils, down the throat, nape of the neck, axilla, vagina,
rectum, etc.
• They should be carefully looked for especially in cases of infanticide where
there is no other cause of death is obvious.

26. Examination of a Punctured wound
from a Medicolegal standpoint
• The position of the wounds in relation to the defects in the clothes may give
some indication about the position of the victim at the time of injury.
• In assessing the depth of penetration it is essential to remember that organ
of the victim lying on an operation table or in a cadaver lying
supine on a mortuary table are not in the same position as
that in an upright living person.
• Multiple stab wounds in a male suggests a homosexual
assault especially when associated with sexual mutilation.

27. Examination of a Punctured wound
from a Medicolegal standpoint
• Homicidal stab wounds are frequently associated with defence wounds
unless the victim is taken unawares or his powers of resistance impaired by
drink, drug, or age.
• Stab wounds may be suicidal, homicidal or accidental-
1. Suicidal stab wounds-
a) of the thorax are situated almost exclusively over the heart area.
b) hara-kiri is an unusual form of suicide where the abdomen is boldly
punctured by a short sword in a sitting position which ultimately results
in death.
2. Homicidal stab wounds-
a) stab wounds over the abdomen, trunk and limbs , other than over
heart, are suggestive of homicidal stab wounds.

28. Examination of a Punctured wound
from a Medicolegal standpoint
3. Accidental stab wounds-
a) from falls while a person is in the act of running with a pointed instrument in his hand or
pocket.
b) Such wounds may also be caused by running over a knife, or falling upon sharp pointed
objects such as broken pieces of glass. The absence of defence wounds clarify the situation.
• From a careful examination of a stab wound, it may be possible to
determine-
1. The nature of the weapon, single edged, double edged, paired, round, pointed stone, or
broken glass.
2. The approximate dimensions of the weapon.
3. The thrusting force from the depth of the wound.
4. The position of the assailant and victim from direction of the wound.
5. The identity of the weapon if a broken piece is found in the wound.
6. Volitional activity.
7. The nature of injury, e.g. homicidal, suicidal or accidental.

29. Dr. Purnima Rani
INTERN
NHMC & H-Delhi