FORENSIC MEDICINE&

TOXICOLOGY

PUNCTURED WOUNDS

Dr. Purnima RaniiNTERN

NHMC & H-Delhi

ABSTRACTThe 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 RaniInternNHMC

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.

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.

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 ona) 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., andc) 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.

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.

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.

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.

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.

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

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 Arrow Scissor

Ice pick

Fork Bayonet

Punctured Wounds

Penetrating Wound: When the weapon enters abody cavity such as the thorax or abdomen, the injuryis 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)

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

Wound of EntryThe 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.

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.

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.

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.

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.

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.

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.

Wound of exit

• This is smaller if a tapering weapon is used and its edges are everted.

Cleavage lines of Langer

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.

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.

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.

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.

Examination of a Punctured wound from a Medicolegal standpoint3. 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.

Dr. Purnima RaniINTERN

NHMC & H-Delhi