Incised Wounds
Incised wounds are sharp cut-like injuries, made by knives or broken glass etc.
The edges of the wound will vary according to the nature of the cutting edge of the object, in that a razor will leave regular margins, whereas an axe may leave the wound margins crushed and bruised, resembling a laceration.
Slash Wounds
These are wounds where the length is greater than the depth, eg a slice wound across the skin. If the wound involves major blood vessels, it can be life threatening, but in general, they are not as serious as stab wounds.
Stab Wounds
These are wounds where the depth of injury is greater than the length. They penetrate more deeply than slash wounds and tend to come into contact with vital organs in the chest and abdomen.
Stabbing is the most common mode of homicide in the UK, due to the strict control of guns.
Stab wounds are caused most obviously by knives, but are also caused by bayonets and swords, as well as scissors and even blunter instruments such as screwdrivers.
These type of wounds have the following features,
they are usually slit-like, but when the object is removed the skin contracts slightly, leaving a wound that is slightly shorter than the blade width. The centre of the wound often widens.
muscle and skin contracture around the wound often obscures the size of the knife blade
the size of the wound depends upon the depth of penetration of the knife, and whether, for example the parallel section of the knife has been reached (ie near to the hilt of the knife)
if the blade is 'rocked' in the wound (ie either the assailant moves the knife around, or the victim moves in relation to the knife), the wound is longer than if the knife is inserted in and out rapidly and in the same direction
irregular or 'V' shaped wounds arise when the knife is twisted in the wound
most knives are single edged, and have a sharp cutting surface whilst the back of the blade is blunt. The wound may be sharp at one end, and blunt at the other. Unfortunately, this is not always the case, as the blunt edge of the knife may split the skin, and resemble a double edged knife wound.
A Single edged bladed knife (with blade guard or hilt)
Double edged blade on the left hand side, single edged blade on the right hand side.
knives that have a handle guard or 'hilt' may bruise the skin around the wound if they are forcefully stabbed into the victim
the depth of the wound is often longer than the length of the knife because of the compressibility of skin and underlying structures, particularly in the abdominal cavity
scissor stab wounds (closed scissors) leave a 'Z' shape
It is important to realise that stab wounds can be made with minimal force. The important factor is the sharpness of the tip of the blade - once it has penetrated clothing and skin, remarkably little force is required to follow through and create a deep knife wound. In addition, the faster the stabbing action, the easier it is to penetrate skin.
For a review of stab wounds, see Forensic Science International journal 52: 107 (1991).
Defence Wounds
A victim of assault can sustain quite characteristic injuries during the course of the assault, as they try to defend themselves, and ward off blows. The photograph illustrates how someone may get wounds on their hands by warding off an attack with a knife.
When warding off knives, the victim usually has multiple incisions across the palmar surfaces of the hands, where attempts have been made to grab the knife blade.
Defence wounds on the hand of a victim of a knife attack
Defence wounds to the forearm of a knife attack victim