A preliminary study evaluating the relationship between force and incised trauma on pig rib bones

Abstract

In forensic contexts, understanding of the complicated relationships between level of force, type of knife blade, and dimensions of incisions remains limited. The purpose of this research was to explore how incisions on pig rib bones vary depending on the type of knife blade and quantity of perpendicular force inflicted. A cutting rig (designed to position a bone, knife, and weights) facilitated the creation of incisions on fleshed rib bones (n = 59), defleshed rib bones (n = 77), and synthetic materials (n = 36). Five different masses of weights (measuring 4381, 8861, 13515, 18267, and 23343 g) were applied to four knife blades (two serrated and two non-serrated blades), with each combination of variables repeated thrice. 3D digital microscopy was utilized to model and measure each incision. The two-way ANOVA found significant differences in depth and length between knife types and levels of force across all sample sets (p < 0.05), with greater perpendicular forces and serrated blades creating longer and deeper cuts. These findings demonstrate that there is a complex relationship between force, type of knife blade, and the related dimensions of incisions.