Modeling and determination of directionality of the kerf in epifluorescence sharp bone trauma analysis

Characteristics of sharp bone trauma can be extremely useful to determine the origin of cut marks and to provide information regarding the context of death. Using human ribs and clavicle bones, this study analyzes the characteristics of bone kerfs made by different bladed implements, thanks to epifluorescence macroscopy. This technique, which is a nondestructive tool that uses autofluorescence of bones, documents bone damage precisely with high resolution. Both qualitative and quantitative criteria are analyzed. Our results identify unique class characteristics on bone lesions, allowing modeling kerf depending on the weapon, regardless of the type of bone that is wounded. Moreover, we demonstrate for the first time microscopic criteria of directionality, using fluorescence excitation. Orientation of cracks, flakes, and lateral pushing back especially helps in determining the tip and the end of the lesion, leading to the position of the aggressor. Kerf wall characteristics and striation location are also very useful. Epifluorescence macroscopy could be a new tool of choice in anthropology through cut mark analysis in establishing how the blade was used and providing details about the blow.