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Trauma - Bodily harm with structural alterations resulting from interactions with physio-chemical agents.

Classification of Injuries

Classification By causative Factors

1. Mechanical or Physical Injuries
1. Injuries by application of blunt force
1. Abrasions
2. Bruise
3. Lacerations
4. Fracture of bone, tooth or joint
2. Injuries by application of sharp edges
1. Incised wound
2. Stab wound
3. Incised-stab wound
4. Chopped wound
5. Sawn wound
3. Injuries by application of teeth
1. Bite marks
4. Injuries by high velocity projectile
1. Firearm wound
2. Chemical Injuries
1. Corrosive poisons
3. Miscellaneous injuries
1. Electrical injuries
2. Radiation injuries
3. Lightning injuries
4. Blast injuries

Medico-Legal Classification

1. Suicidal (Self-inflicted)
2. Homicidal (Injuries inflicted by others)
3. Accidental
4. Defense wounds

Classification in relation to moment of death

1. Ante-Mortem wounds
2. Post-Mortem wounds

Mechanical Injuries

• These are injuries produced by physical violence
• The injury is a loss of natural continuity of any of the tissues of body.

Factors Responsible for mechanical injury

1. Force
2. Area over which it acts
3. Specific effect of force
4. Time taken

Weapons of Offence can be grouped into :

1. Hard Blunt Object
1. Stick
2. Stone
2. Light weapon with sharp edge
1. Knife
2. Razor
3. Heavy weapon with sharp edge
1. Axe
2. Saw
4. Pointed weapons
1. Needle
2. Arrow

Abrasions

• Abrasions is a destruction of the skin that usually involves the superficial layers of the epidermis only.
• Abrasions is caused by lateral rubbing actions at the moment of blow, a fall on a rough surface, dragging in a vehicular accident, actions of finger nails.

Abrasions are of four types

1. Scrathes
2. Grazes
3. Pressure Abrasions
4. Impact Abrasions

Medico-legal importance of Abrasions

1. They give an idea about site of impact
2. They may be the only external sign of a serious internal injury
3. Patterned abrasions are helpful in relating the wounds to object that produced them.
4. Age of the wound can be determined.

Bruises

• Bruises is an effusion of blood into the tissue due to rupture of blood vessels caused by the action of blunt object
• In Bruises, there is a painful swelling, tearing of subcutaneous tissues usually without destruction of skin.
• Size : Vary from pinhead to large collections of blood in the tissue.
• The bruise is usually round or oval, but it may indicate the nature of weapon used.
• A blow with solid body, such as hammer produces rounded Bruise.
• A blow with rod or stick produces parallel bruises.

Size and shape of Bruises are modified by following factors

1. Condition and Type of Tissue
1. If the body is vascular and loose, such as face, scrotum, a small force can cause large bruise.
2. If the tissue is covered with thick dermis, such as scalp, palms and soles, a moderate blow can cause small bruises.
2. Age and Sex
1. Children bruise easier because of softer tissues and delicate skin.
2. Old persons bruise easily because of loss of flesh and cardio vascular changes.
3. Color of skin
1. Bruising is more clearly seen in fair-skinned persons than in those with dark skin
4. Diseases
1. When the vessels are diseased as in case of Atherosclerosis, bruising occurs very easily.

Complication of Bruise

1. A bruise may contain 20–30 ml of blood or even more.
2. Multiple bruises can cause death from shock and internal hemorrhage.
3. Gangrene and death of tissue can result.
4. Bruise can serve as a site for strong bacterial growth.

Medico-legal importance of Bruise

1. Patterned bruises may show relation between the victim and weapons
2. Prescription of injury can be determined
3. Character of injury may be known from its distribution

Lacerations

These are tears of skin, mucous membrane or muscular produced by application of blunt force.

Types of Lacerations

1. Split Lacerations
1. Occurs by crushing of skin between two hard objects
2. Stretch Lacerations
1. Occurs by overstretching of skin when it is fixed.
3. Avulsion
1. Produced by sufficient force applied at an acute angle to tear off a portion of traumatized surface of an organ from its attachment.
4. Tears
1. Tearing of skin and tissues can occur from impact against irregular sharp object.

Complications of Lacerations

1. Laceration of internal organ may cause severe bleeding.
2. Pulmonary fat embolism may occur due to crushing of subcutaneous tissue.

Medico-legal importance of Lacerations

1. Type of Laceration may indicate the cause of injury and shape of blunt weapon.
2. Foreign bodies in wound may indicate the circumstances in which crime has been committed.
3. Age of injury can be determined.

Incised Wounds

• An incised wound is a clean cut through the tissues that is longer than it is deep.
• It is produced by friction against the tissue by an object having a sharp-cutting edge.

Characteristics of Incised wounds

1. Shape - It is spindle shaped due to greater retraction of edges in centre
2. Length - Length is greater than width & Depth
3. Width - Width is greater than edge of weapon
4. Depth - Incised wounds are deeper at their beginning because more pressure is excreted on knife at this point.

Medico-Legal Importance of Incised wounds

1. It indicates the nature of weapon
2. Age of injury can be determined
3. Character of wound may indicate more of infliction (Suicidal or accidental)

Stab Wounds

• Stab wounds are deep wounds produced by point end of a weapon.

Varieties of Stab Wounds

1. Penetrated wound
1. Wound terminates inside a body cavity
2. Perforated wound
1. Part of weapon passes through the whole thickness of any part of body
3. Punctured wound
1. Wound without penetration to a body cavity
2. Here the tip of weapon terminated inside the body except in a body cavity

Characteristics of Stab wounds

1. Shape
1. Circular with pointed conical weapon
2. Irregular with cylindrical weapon without a pointed end
2. Length
1. Length of external wound corresponds to breadth of the blade of weapon
3. Breadth
1. Breadth of wound corresponds to thickness of blade of weapon

Complications of Stab wounds

1. Internal hemorrhage is larger
2. Injury of vital internal organs is more common
3. Wound may become infected
4. Air embolism may occur

Medico-legal importance of Stab wounds

1. Shape of wound may indicate type of weapon
2. If a broken fragment of weapon is found, it may identify the accused
3. The depth of wound indicates the force of penetration
4. Age of Injury can be determined.

Incised-Stab wound

• It is a stab wound that is converted to an incised wound
• It combines characteristics of stab and incised wound

Characteristics of Incised-Stab wound

1. Shape
1. It depends more on the shape of the weapon.
2. When double-edged pointed weapon is used, the external wound is elliptical
3. When single-edged pointed weapon is used, the external wound will be triangular

Chopped wounds

• They are deep gaping wounds caused by a blow of a sharp-cutting edge of heavy weapon
• They may show slight Abrasions and Bruising
• Margins are sharp
• Most of these injuries are homicidal

Sawn Wounds

• Caused by disk saw

Characteristics of Sawn wound

1. Edges are rough with fine rags
2. Surface of injured bones are arch-like traces
3. There are multiple stab wounds reflecting the sizes of teeth of saw

Bite Marks

• These may be Abrasions, Bruises or Lacerations or may be sometimes combination of these three
• Animal bite is U-shaped
• Human bite is Circular shaped

Gunshot Injuries

Classification of Firearms

1. According to Purpose
1. Battle (Pistols, Rifles)
2. Haunting (Barreled Guns)
3. Sports (Pistols, Rifles)
4. Special (Alarm Pistols)
2. According to length of barell
1. Long-barreled (Rifles, Machine guns)
2. Short-barreled (Pistols, Revolvers)
3. According to property of barell
1. Rifled (Pistols, Revolvers)
2. Smooth-bored weapons (Short guns)
3. Combined (haunting Rifles, Sports guns)
4. According to Caliber (Diameter)
1. Small Caliber (4–6 mm)
2. Medium Caliber (7–9 mm)
3. Large Caliber (>9 mm)
5. According to Mechanism of shot
1. Automatic (Machine guns)
2. Semi-Automatic (Pistols)
3. Non-Automatic (Haunting Rifles)

Principal types of Firearms are

1. Smooth bored Firearms
1. In these weapons, the bore (inside the barrel) is perfectly smooth
2. Barrel length is about 24–30 inches.
3. Examples : Short guns, Muskets, gunshots
2. Rifled fire arms
1. Bore is rifled i.e, cut longitudinally with number of spiral groves, which run parallel to each other and its is called Rifling
2. Caliber of rifled bore is distance between opposite bore and it is about 7–9 mm.
3. Examples : Pistols & Revovlers

Firearm Injuries

• Wounds caused to the body tissue due to impact and passage of a missile discharged from a firearm

Process of Firearm Injury

1. A moving projectile has kinetic energy proportional to its weight and velocity.
2. Wound if produced by transfer of kinetic energy to tissues.
3. If a projectile does not exit the body, then all of its kinetic energy has been transformed to body.

Distance of a shot

• Distance between muzzle and surface of injured body

Classification of Distance of a shot

1. Contact shot
2. Close shot
1. The entrance wound is circular with inverted edges and is surrounded by blackened, tattooed and burnt area.
2. The blackening can be wiped off the skin.
3. Partially burnt powder grains will be driven into skin producing tattooing. This cannot be wiped off
3. Long shot
1. The entrance wound is smaller than the bullet due to elasticity of the skin, circular & margins are inverted.
2. There is no burning, no blackening and no tattooing.

Bone Fractures

• It is a break in continuity of a bone
• If the break is due to trauma, it is known as traumatic fracture
• If the break is due to pre-existing disease, then it is called as pathological fracture
• Fractures showing multiple breaks are known as comminuted fractures
• If skin above the fracture is intact, then it is called as Closed fracture
• If skin above fracture is lacerated, then it is called as Open fracture.

Fracture of Skull

• Skull may fracture as a result of direct or indirect violence

Types of Fracture of Skull

1. Fissured Fracture
1. Linear fracture involving the outer or inner table
2. Depressed fracture
1. Caused by heavy weapons with limited striking surface (hammer)
3. Comminuted fracture
1. Fracture by blows from weapons with a large striking surface (fall from heights)
4. Gutter fracture
1. When part of thickness of skull bone is removed, then it is called as Gutter fracture
5. Penetrating fracture
1. Clean cut opening due to penetrating weapon
6. Elevated fracture
1. It is due to blow from a moderately heavy sharp edged weapon

Common sites of Fracture of Base of Skull

1. Anterior cranial fossa
2. Middle cranial fossa
3. Posterior cranial fossa
4. Around the foreman magnum

Fracture of Face

• Fractures of mandible, maxilla, zygoma are produced by assaults

Types of Fracture of Face

1. Dento-alveolar fractures
1. Direct force applied anteriorly or laterally causes separation of fragments of mandible
2. Le Fort I
1. Transverse fracture of maxilla, above the apices of teeth, through nasal septum
3. Le Fort II
1. Fracture has same path posteriorly
2. As it proceeds anteriorly, it curves upwards near the zygomatic-maxillary sutures through the inferior orbit rim onto the orbital floor, through medial orbital wall and across the nasal bones & septum.
4. Le Fort III
1. Transverse fracture of maxilla that goes through the naso-frontal suture, through medical orbital wall and frontal-zygomatic suture.

Fracture of Ribs

Types based on Cause

1. Direct Violence
1. Depending on where the force is applied, one or more underlying ribs might be fractured.
2. The fractured ribs can contuse the underlying lung parenchyma
3. Fracture of first thoracic rib are associated with severe injuries to the trachea-bronchial airway.
2. Indirect Vioence
1. Severe anterior-posterior compression of chest, may fracture the ribs on their curved lateral portions.
2. If it is posterior-anterior, ribs tends to fracture near the spine.
3. Pathological rib fracture occurs in primary bone disease & tumors of bone.
4. Introgenic rib fracture occurs during CPR (Cardio-Pulmonary Resuscitation)

Fracture of Extremities

Types of Fractures of extremities

1. Direct Fracture
1. Produced by direct application of force
2. When a blunt object impacts a long bone, cracking of bone on opposite side occurs
3. With significant impact, there is a crushing on the side where force is applied.
2. Indirect fractures
1. Produced by force acting at a distance from the fracture site.
2. In this regard, the bone is weaker to tension(stretching) than compression.