Virtual Casting of Stab Wounds in Cartilage Using Micro-Computed Tomography

In homicidal stabbings using a serrated knife, stab wounds involving costal cartilage leave striations on the cut surface of the cartilage from the serration points on the blade edge. Class characteristics of the serrated blade can be determined from the striation marks, and individualizing characteristics may be seen also. The traditional method for recording the striation marks involves the pernickety technique of casting with dental impression material. We assessed the potential utility of micro-computed tomography scanning of the stab track as a technique for nondestructive recording of striation patterns and virtual casting of them. Stab tracks in porcine cartilage, produced with a coarsely serrated blade, were scanned with a bench-top micro-computed tomography scanner. The typical irregularly regular striation pattern could be demonstrated, and the images manipulated, using proprietary software to produce a virtual cast. Whether the technology will have sufficient resolution to image not only class characteristic tool marks but also the much finer individualizing tool marks remains to be evaluated, but the technology shows considerable promise.