A laceration wound is a type of mechanical injury caused by hard and blunt force impact characterized by the splitting or tearing of tissues. This happens when the skin loses its elasticity. The laceration wound is also known as tears or ruptures. Localized portions of tissue are displaced by the impact of the blunt force, which sets up traction forces and causes tearing of the tissues.
A laceration wound is different from an incised wound because the continuity of the tissue is disrupted by tearing rather than clean slicing. The object used to cause the wound is pulled obliquely against the tension of the skin. It crushes and stretches a broad area of the skin, which then splits in the center causing a tear.
Depending upon the presence or absence of vital reaction and, of course, the extent of bleeding, coupled with bruising of the margins helps to distinguish between antemortem and postmortem laceration. Eversion and gaping of the margins is usually seen when it has been inflicted during life but here again, caution must be exercised as the muscles can contract for some time after death, and further, the posture of the body at and after the time of death may cause gaping simply due to passive gravitational effects.
Types of Laceration Wounds
1. Split Laceration
They are also known as incised-looking lacerations. They are caused due to a blunt force that splits the skin most frequently when the skin and the soft tissues are crushed between the underlying bone and the impacting force.
Split lacerations occur when the soft tissues are ‘sandwiched’ between a hard unyielding deeper structure and the agent applying the force. Scalp lacerations are the typical examples that occur when the scalp tissue is crushed between the skull and some hard object.
When the skin is closely applied to the bone and the subcutaneous tissue is scanty, blunt force may produce a wound by a linear splitting of the tissues that resembles an incised wound. Such wounds may, therefore, be termed as ‘incised-looking wounds’. The sites notorious for the production of such wounds are the scalp, face, eyebrows, zygoma, iliac crests, perineum, shin, etc.
2. Tear Laceration
It is the most common type of laceration wound. The tearing of the skin and subcutaneous tissue occurs from localized impact by hard and blunt force. The acting force from the object or weapon rips the skin or tissues producing the laceration.
3. Boxer’s Laceration
These are seen in boxers who are actively boxing. This laceration happens when a boxing glance presses on the orbital margin.
4. Cut laceration
It is caused by a not-so-sharp-edged weapon.
5. Stretch laceration
It happens due to overstretching of the skin unless it ruptures. This type of laceration is caused due to pulling force.
For example, If the pressure is applied over the thigh stretching the skin toward the knee, then such force can cause laceration along the inguinal line. Stretch mark-like laceration or striae-like laceration are also classified under this type of laceration.
6. Avulsion Laceration
These are also known as flaying injuries or grind lacerations. It happens due to grinding compression of the tissues to such an extent that the skin gets detached from the deeper tissues. A large area of the skin gets rolled off from the body part.
7. Crush Laceration
This type of injury will cause total or partial amputation of the affected body part. These are associated with avulsion or stretch laceration.
8. Patterned Laceration
These patterns are not prominent like that observed in abrasion or bruising but some weapons can produce recognizable patterns. For example, a blow with a hammerhead with a circular face may produce a circular or an arc of circle-shaped laceration. A linear laceration is produced due to long and thin objects. The heavy focal blow will cause a linear or a stellate-shaped laceration.
When a blunt force is applied, laceration of the internal organ may happen. If a kick is applied over a region like an abdomen, it can cause internal injury to the pancreas. The complications of lacerations are death, hemorrhage, shock, infection, pain, and dysfunction of the affected body part.
Features of Laceration Wounds
- It is a three-dimensional injury with length, depth, and width.
- These wounds gape open.
- The margins will be irregular and ragged and maybe slightly inverted.
- Crushing and tearing nature of the production of lacerations, there is usually associated abrasion or bruising.
- Edges of laceration may give an indication of direction, in which the blow or force was applied.
- Irregularly torn fibrous tissue, blood vessels, and nerves.
- Lacerated wounds do not bleed much as the vessels are crushed and torn but not cut evenly.
- Lacerations over the hairy areas will show hair bulbs crushed or torn and the crushed hair bulbs may get thrust into the depth of the wound.
Laceration wounds have medicolegal importance because it helps to identify the cause of injury, nature of the injury can be ascertained, whether it is accidental, suicidal or homicidal.
Understanding the wound and its features helps to understand the type of lacerated wound, age of the injury, the direction of the application of force, whether antemortem or postmortem injury can be estimated.
Foreign bodies present in the wound will help in identifying the offending weapon, place of incident, and such information. Care should be taken to not confuse it with an incised wound.