A histological comparison of non-human rib models suited for sharp force trauma analysis.

Cut marks provide essential knowledge to interpret which and how tools were used, both in archaeological and forensic context. Lots of studies focused on experimentally produced cut marks on animal models to develop methods for stabbing incidents. However, animal models are criticized to be morphologically different in comparison to human bones. This study analyzed the bone composition and experimentally obtained cut marks done on ribs from humans, pigs and goats. Methods included a qualitative description of differences between the species and a quantitative analysis of the cut mark proportions in histological thin sections and micro CT scans. The results indicated that especially the cortical bone of non-human ribs was different in comparison to human bone tissue as they were more robust and usually juvenile. Plexiform bone dominates and remodeled lamellar bone is rarely visible. The knife impact tends to create debris inside the cut mark and stress fractures along lamellae and cement lines perpendicular to the cut mark. Moreover, entheses of the intercostal muscles are always affected by the incision. Pig ribs were shown to be better suited as a model for sharp force trauma than goat ribs in comparison to humans. Though, plexiform bone and non-remodeled bone made it not quite ideal. We suggested to use bone material from animals used for breeding instead of meat production as they are slaughtered at higher ages.