Lacerations and their Forensic Significance

Lacerations are tears or splits of skin, mucous membranes, muscle or internal organs produced by application of blunt force or broad are on the body. They are also called tears or ruptures. The margins of the laceration may suggest the direction in which the force was applied. Types of lacerations are split lacerations (crushing of the skin between two hard objects), stretch lacerations (overstretching of skin), avulsion, tears etc.

Types of Lacerations

• Split laceration – This is the most common type of laceration and it occurs when an object hits the skin and compresses it against the bone, opening a wound. Example: A baseball bat hits the head and the impact causes a wound.
• Stretch laceration – when a hard object hits the skin and causes it to overstretch and then tear, causing a skin flap. Example: A boot kicks a shin, causing a wound to open with skin flapping over it.
• Crush laceration – when a crushing force causes the bones to break and protrude out of the skin. Example: vehicular accidents where a part of a car crushes the shins or the legs.
• Avulsions – this happens when a grinding force causes the skin to separate from underlying tissues. Example: A wheel runs over a limb or a body part which causes the skin to come off like a glove.
• Tearing – when an object hits the skin and it is pulled in opposite directions causing a tear. Example: A jagged knife enters the skin.

Characteristics and Forensic Significance of Lacerations

• Margins are irregular, ragged and uneven and their extremities are pointed or blunt.
• Bruising is seen either in the skin or the subcutaneous tissues around the wound.
• Deeper tissues are unevenly divided with tags of tissue at the bottom of the wound bridging across the margin.
• Hair bulbs are crushed.
• Haemorrhage is less because the arteries are crushed and torn across irregularly.
• Foreign matter may be found in the wound.
• Depth varies according to the thickness of the soft parts and the degree of force applied.
• A laceration is usually curved.
• The skin on side of wound opposite to direction of force is usually torn free or undermined.

Lacerations after death can be distinguished by the absence of bleeding. As has been intimated above, sometimes it can be difficult to differentiate a laceration from an incised wound.

The following points will help you in making that differentiation:

1. Examination of the margins, using a magnifying glass if necessary, will show irregularity in a laceration.
2. Not uncommonly a laceration has an associated abrasion and/or a contusion.
3. Presents of swallow tails at the ends of a lesion, diverging at an angle from the primary lesion indicates a laceration.
4.  Bridges of tissue are seen extending from one side of the laceration to the opposite. In an incised wound no such bridges are formed.
5. When a laceration appears over bone, there is no evidence of linear injuries in the underlying bone.
6. Lacerations of the scalp often will show intact hairs extending across the defect. An incised wound will show cutting of the hairs.

Forensic Significance

• The type of laceration may indicate the cause of the injury or the shape of the blunt weapon.
• Foreign bodies found in the wound may indicate the circumstances in which crime has been committed.
• The age of the injury can be determined.