Reconstruction of knife attacks attempts to assess the relative positions of the assailant to the victim, and the characteristics of the surface wounds may assist in determining angle of impact. For example, the edges of one side of the wound may be ‘undercut’ or ‘shelved’ when a knife enters the skin at an angle. #
If a knife is passing from below the umbilicus towards the nipple, for example, subcutaneous tissue may be visible at the inferior (bevelled) surface, and not the superior (undercut) surface.
Other indications of direction of impact include superficial abrasions or small ‘nicks’ in the skin at the entry point. The examination of clothing may also reveal useful information about the direction of thrust, and should be retained and examined in all cases.
Attempts have been made by researchers over the years to find alternative methods of demonstrating both depth of penetration, and the general characteristics of a knife wound, with a view to matching the measurements with a suspect weapon.
Such techniques have included the use of latex solutions being poured into the wound tract. However, these techniques have proved unsatisfactory due to the leakage of the solution through tissue planes and around the wound.
Methods using probes have also proved difficult, and have sometimes damaged the tract, thus distorting it’s dimensions. Clearly, non-invasive and non-destructive techniques would be ideal, and newer imaging modalities, such as MRI may provide alternative solutions in the future. (For example, see Thali et al 2002).
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