16.1: Introduction

• Trauma — a wound or injury, especially produced by external force.

• Legally, it is defined as any harm whatsoever in nature illegally caused to the body, mind, reputation, or property.

• Clinically, it is defined as breach or dissolution of the natural continuity of the tissues of a living body by actual physical violence.

Classification of Trauma

1. Legal Classification:

   1. Simple

   2. Grievous

2. Medicolegal Classification

   1. Mechanical

   2. Thermal

   3. Chemical

   4. Electrical/lightning

   5. Radiation

16.2: Mechanical Trauma

• All injuries sustained due to physical violence to the body constitute mechanical trauma or mechanical injury.

Mechanism of Mechanical Trauma

• Impact of a Moving Object: Here the trauma is due to the impact of a moving object on a relatively non-mobile victim.

• Impact of a Virtually Non-moving Object on Actively Moving Victim: Here the mechanical trauma is due to the impact of moving victim who directly hits against a non-moving object.

Classification of Mechanical Trauma

1. Blunt Force Trauma: It is injury produced by weapons or objects with blunt edges or surfaces.

   • Abrasion

   • Contusion

   • Laceration

2. Sharp Force Trauma: It is injuries produced by weapons or objects with sharp cutting edges.

   • Incised wound

   • Stab wound

   • Chop wound

3. Firearm Injuries: These are injuries produced by firearms.

   • Injuries by rifled firearms (gunshot injuries)

   • Injuries produced by smooth bore firearms (shotgun injuries)

16.3: Abrasion

• Abrasion — a superficial injury, inducing displacement of only epidermis in the skin by friction.

Various causes leading to development of an abrasion are:

• Fall on a rough surface

• Blow with blunt weapon

• Dragging by a vehicle

• Hurt by fingernails, thorns, teeth bite, etc.

Classification of Abrasions

1. Scratches — linear injuries due to a sharp object, e.g. pin, thorn, fingernail, etc.

2. Grazes: These are injuries due to frictional force of rubbing by a blunt object moving with great force.

3. Brush Burns: These are grazes involving a wider area due to the frictional force of rubbing against a rough surface, and resembles a burn injury.

4. Rope burns: These are due to heat produced by frictional force of a rope against the skin.

5. Pressure Abrasion: This will be caused by direct impact or linear pressure of a rough object over the skin accompanied by slight movement directed inwards, resulting in crushing of superficial layers of the cuticle with some bruising underneath.

6. Impact Abrasions: These are due to direct impact or pressure of some object, which on crushing the cuticle casts a reproduction of its shape and surface marking upon the skin.

Differential Diagnosis

An abrasion may be mistaken for:

1. Postmortem Abrasion: Though it grossly looks like antemortem abrasions, it is different when examined closely.

2. Postmortem injuries: Insects and crustaceans produce these.

3. Excoriation of the skin by excreta: These are due to contamination of the skin by dried up fecal matter, and can be washed with water.

4. Pressure sores: These are due to pressure necrosis of the skin in a person who is bedridden for long-time and not under proper care.

Medicolegal Importance of Abrasions

• Can provide clues on site of impact and direction of force

• Can be the only external sign of a severe internal injury

• Can help to identify causative weapon, e.g. imprint abrasions

• Can help to determine time since injury

• Can help to assess the motive, e.g. ligature mark of hanging, strangulation, etc

• Abrasions may also be developed on a cadaver (postmortem abrasion).

16.4: Contusion

• Contusion — a hemorrhage into the skin, or into the tissues under the skin or both, as a result of rupture of small blood vessels, especially capillaries by a blunt impact.

Classification of Bruises

1. Superficial Bruises: These are usually seen raised above the surface of the skin (swelling) due to the infiltration of blood into the subcutaneous tissues.

2. Deep/Delayed/Migratory/Ectopic Bruises: These may also produce a mild swelling and may take more time to appear externally than superficial bruises.

3. Patterned Bruises: These are bruises that take round or oval shape. Sometimes it could also take up the shape of the causative weapon used.

Factors Affecting Bruising

• Type of Tissue/site involved:

  • More vascular parts such as the vulva, scrotum, etc. can develop big bruises with little force.

  • Stronger parts such as palm, sole, etc. develop smaller bruises with great force.

• Age: Children and elderly people can be more easily bruised than young adults.

• Sex: Females can be more easily bruised than males.

• Color of skin: Fair skin individuals develop bruises clearly, which are easily recognized.

• Natural diseases

• Gravity shifting of blood: This factor is many times responsible for the appearance of bruises at a site other than the site of injury.

Differential Diagnosis

1. Artificial Bruises (Fabricated wounds): These are skin lesions produced by the application of certain irritant substances such as plumbago rosea-roots/twigs of the plant and marking nut juice over skin, which resembles a bruise, apparently.

2. Post Mortem Bruising: Bruises cannot be produced after 2 minutes of death.

   1. Small bruises can be developed by great violence, even up to 3 hours of death.

3. Can be misinterpreted as Post Mortem Lividity.

Medicolegal Importance

• Bruise is of Lesser Importance than an Abrasion.

  • Size of a bruise may not correspond to the size of the weapon used

  • Bruise may appear late after injury

  • Bruise may appear in far away regions of the body from the actual site of injury.

• Contusion can Help Law and Criminal Investigation

  • Causative weapon

  • Time since injury

  • Degree of violence

  • Characteristics and manner of injury

16.5: Laceration

• Laceration — a disruption of the continuity of tissue, produced by stretching or crushing type of blunt forces.

Classification of Laceration

1. Split Laceration — occurs when the skin is crushed between two hard objects, e.g. incised-like laceration of the scalp and forehead.

2. Stretch Laceration — occurs due to the overstretching of the skin, beyond its elasticity.

3. Avulsion — a lesion wherein the skin separates by tearing from the underlying tissues or peels off and overhangs the wound.

Medicolegal Importance

1. Lacerations can provide clues regarding the motive of injury:

   • Accidental — commonly seen anywhere on exposed parts of the body

   • Homicidal — especially noticed on non-accessible parts of the body especially in assault cases

   • Suicidal —very rarely seen as they are painful to produce.

2. Foreign matter in the wound could give clues about the weapon used.

3. The skin flap, which overhangs the cut margin can indicate the direction of force applied.

16.6: Incised Wound

• Incised Wound — a clean cut through tissues by an object with a sharp cutting edge.

Characteristics of Incised Wound

1. Spindle-shaped due to gaping by skin elasticity, zigzag where skin is lax.

2. Clean, well-defined and averted.

3. Minimum if smaller vessels are cut, more if bigger vessels are cut.

4. It is greater than width/depth.

5. It is greater than the edge of the weapon.

Examination of Incised Wound

• Direction of the Wound: This is established by the phenomena of tailing of the wound.

• Beveling cuts: Here one edge of the wound overhangs the other, and is due to penetration of the blade at an angle, which can decide the relative position of the victim, and assailant.

• Age of Incised Wounds (Time since Injury): It is assessed roughly by the stage of wound healing grossly as well as microscopically at the time of examining.

Medicolegal Importance

• The wound may have to be distinguished from an incised-like laceration.

  • Hesitation cuts / tentative cuts — parallel superficial cuts suggestive of suicidal motive, seen in the vital parts of the body such as neck, chest on left side, wrists, etc. and are inflicted by the victim, prior to the final fatal deep cut or stab.

  • Defense cuts — incised wounds suggestive of homicidal motive with sharp weapon, seen on a victim’s forearms and hands, while making either an attempt to grab the weapon by its blade resulting in active defense wounds, in order to protect himself from the attack resulting in passive defense wound.

• The wound could also give clues on weapon causing the wound, time since injury, site of impact and direction of force.

16.7: Stab Wounds

• Stab wounds — wounds produced by sharp pointed objects penetrating the skin and underlying structures.

• Volitional Activities — the actual voluntary acts or physical activity observed in a victim of fatal stab injury.

Examination of the Wound

• It can be seen anywhere, especially chest/abdomen.

• Depends on size of the weapon used.

• Wound usually corresponds to the type of weapon used:

  • If the weapon is a single-edged knife, it will be wedge / triangular, blunt edge of the knife corresponds to the base of the triangle.

    • It can also produce special effect fishtailing.

    • This is produced by the blunt edge of the weapon, which usually forms the base for the triangular wound.

  • If the weapon is a double-edged knife/dagger, the wound would be spindle shaped.

  • If the weapon is a nail, screwdriver, etc. the wound would be circular shaped.

• A wound cutting across these lines produces maximum gaping, while a minimum gaping is seen if the wound is along the direction of fibers.

• Usually equal to the breadth of the weapon. It will be more if the weapon is pulled upwards or downwards, during insertion or withdrawal.

• More than thickness of the blade—gaping.

• Depth is either equal to or a little less than the length of the weapon used for stabbing it could be more in yielding areas like abdomen.

• Margins are clean and sharp but may show few abrasions around, if the hilt/handle of the knife touches the skin.

• Direction is indicated by the undercutting of the skin at the wound of entry or by the track taken by a blunt probe.

Classification of Stab Wounds

1. Punctured wound: Here the weapon just enters into the part of the body without entering into any of the body cavity.

2. Penetrating wound: Here the weapon just enters into the body cavity producing only one wound.

3. Perforating wound: Here the weapon after entering into one side of the body will come out through the other side, producing two wounds.

   • Wound of entry — through which the weapon enters the body. It is larger and with inverted edges.

   • Wound of exit — through which the tip of the weapon emerges out of the body. It is usually smaller with everted edges.

Complications of Stabbed Wounds

• Exsanguinations and hypovolemic shock.

• Air embolism

• Secondary infections

• Pneumothorax

• Injury to vital organs

Medicolegal Importance

• Vendetta murder — a phenomena of revengeful homicide wherein the assailant, on his or her victim stabs several times, especially mutilating the face by dragging the knife in a crisscross manner.

• Concealed punctured wounds — these are punctured wounds made by pins and needles, usually difficult to locate by naked eye examination and missed by the inexperienced autopsy surgeon.

16.8: Chop Wounds

• Chop wounds — injury produced by a blow with the sharp cutting edge of a fairly heavy weapon like an ax, hatchet, saber, etc.

• Lesion produced is always dangerous and fatal due to:

  • Bleeding

  • Usually involving deeper viscera.

Medicolegal Importance

• Chop wounds are usually seen on exposed parts such as head, neck, face, soldiers and extremities.

• Usually they are accompanied by severe injury to underlying bones and organs.

• Majority are homicidal.

• A few are accidental due to machinery, such as—propeller injuries.

• Very rarely, they could be suicidal.

• Wound examination could reveal clues regarding causative weapons.