Mechanical injuries are Injuries caused by physical violence to the body. Based on the causative forces, mechanical injuries can be divided into blunt force injury, sharp-edged weapon injuries, and piercing weapon injury. These injuries can be inflicted accidentally, or in situations at work, sports, private life, and so on. Lacerated wounds are due to blunt force, stab wounds are caused by a piercing weapon, and incised wounds are due to a sharp-edged weapon.
Incised wounds are produced by a sharp-cutting weapon. The force when delivered over a very narrow area corresponding with the cutting edge of the blade of the weapon will cause orderly solution of the skin and tissues. Incised wounds can be produced by striking the body with a sharp cutting edge, due to swiping or drawing action of the weapon on the body which will produce tailing at one end of the wound, or by sawing. The sawing action will produce multiple wounds on the skin at the beginning which will all merge into one at the end.
A lacerated wound is caused by hard and blunt force impact characterized by the splitting or tearing of tissues when the skin loses its elasticity. The laceration is also known as tears or ruptures. The continuity of the tissue is disrupted because of the tearing. There are different types of laceration known as stretch laceration, split laceration, avulsion, tear, crush, and cut lacerations.
Stab wounds are piercing wounds that are produced by the application of mechanical force along the long axis of a narrow or pointed object. These types of wounds can be penetrating or perforating.
Difference Between Lacerated, Stab and Incised Wounds
|Traits||Lacerated Wounds||Stab Wounds||Incised Wounds|
|Manner of production||Caused by blunt weapon or object||Can be produced by both blunt or sharp weapon||Caused by sharp weapon or object.|
|Site||Mostly over a bony prominence||Anywhere, but commonly seen in the chest and abdomen||Anywhere|
|Margin||Irregular and undermined||Clean-cut and parallel edge. If a blunt weapon is used then it will be lacerated.||Smooth, even, Clean-cut, and everted.|
|Abrasion on Edges||Usually present||Absent||Absent|
|Bruising||Present over surrounding and underlying tissues||Rare||Not generally seen|
|Shape||Usually irregular||Linear or irregular||Linear or spindle-shaped|
|Dimension||Longer than deeper||Depth will be more than length and breadth||Often gaping and longer than deep|
|Hair bulb||Crushed or torn||Usually clean cut||Cleanly cut|
|Hemorrhages||Slight except scalp and external||Mostly internal||Usually profuse and external. Spurting Of the blood can be seen.|
|Depth of the wound||Small strands of tissues at the bottom bridge across margins||Structures will be cleanly cut.||Structures will be cleanly cut to the depth of the wound.|
|Bones||Maybe fractured||Maybe punctured||Maybe cut|
|Clothes||Maybe torn||Maybe cut||Maybe cut|
|Foreign bodies||Mostly present||Usually absent||Absent|
The forensic examination of the injuries caused by the different types of blunt or sharp objects is an important section under forensic-medical traumatology.
It is important to know about the features and characteristics of the various types of weapons as they give clues about the type of weapon used, the force of impact, and the manner of death. Careful observation helps to avoid differential diagnosis and helps in the effective investigation process.