Bio-mechanics of a Slash Attack

 

 

Slash wounds occur as a result of tangential movements of sharp implements across the skin surface, for example razors, broken glass, knives, swords etc. They are often deeper at their origin, and tend to be more superficial at their termination. They are often aimed at the head or neck with fewer injuries aimed at the upper limb and trunk.

Incised wounds have cleanly divided edges, compared with lacerations, whose edges are crushed and abraded. The wounds may be jagged but are not usually abraded (but see below).

The nature of the wound edges is a direct reflection of the sharpness of the edge/ blade. A blunt cutting edge is more likely to produce wound margins that are slightly abraded or bruised.

There are no tissue bridges within the wound, as the sharp implement cleanly divides all soft tissue structures in its path.

Slash wounds often bleed profusely, as vascular structures are cleanly divided (unlike the crushing of arteries found in lacerations) and spasm is diminished.

The presence of foreign material in the depths of the wound may complicate healing, but is less of a problem than with lacerations. All slash wounds should be thoroughly examined in the emergency department in order to assess potential damage to underlying deeper structures, such as neurovascular bundles.

The origin of a slash wound is often said to be deeper than it’s termination, but this generalisation is often complicated by the relative positions of the parties involved as well as the anatomical location injured. Fights are not static events, and it is often difficult to determine relative positions during an assault, unless it has been reliably witnessed.

The abdomen is often said not to be a favoured target during an assault (Knight 1996) – the main targets being the face, head, neck and chest.

However, recent research by Bleetman et al (2003 (b)) undertaken to determine the favoured targets for slash injuries seemed to indicate that abdominal slash wounds are a favoured site of attack for some groups of assailant (in the case of this research, soldiers trained in close quarters combat).

Eight types of slashing motion were identified with 23% slashing in a single long stroke; 31% a single short stroke, whilst the other research volunteers favoured a combination of long and short slashes. In clinical practice only 11% of victims showed signs of more than one slash stroke.

Emphatic generalisations should not therefore be made regarding the likely causation of a slash wound on a person’s abdomen, in the absence of any corroborative evidence.

Further research ( Bleetman et al 2003 (a)) utilising students identified 2 patterns of slash attack – the ‘chop and drag’ (generating high peak forces and velocities), and the ‘sweeping motion’. This was more common, and it was found that diagonal slashes were favoured (particularly long slashes (averaging 34 cm) from shoulder to waist. Only 18% of subjects favoured a horizontal slash across the body.

The forces generated in slash attacks were found to be peaking at 212 N (with a maximum velocity of just under 15 m/s). This compares with a peak force of 800 N generated in a human stab attack.

Reference:

Bleetman A., Watson C.H., Horsfall I., Champion S.M. (2003 (a)), ‘Wounding patterns and human performance in knife attacks: optimising the protection provided by knife resistant body armour’, Journal of Clinical Forensic Medicine 10(4) 243-248

Read more: http://www.forensicmed.co.uk/wounds/sharp-force-trauma/slash-wounds/