Interpreting Injury Mechanisms of Blunt Force Trauma from Butterfly Fracture Formation.
According to biomechanics of fracture production during blunt impact, tubular bones are subject to compressive (impact site) and tensile (opposite impact site) forces; this causes bones to break in tension before compression, producing Y-shaped fracture patterns with breakaway (butterfly) fragments. In current forensic models, the side of the bone exhibiting the breakaway fragment is designated the impact side, with initial breakage occurring opposite. Fracture production and patterning of blunt impacts to 255 sheep femora were analyzed. Contra the existing model, only 60% of complete butterfly fractures exhibited impact side breakaway fragments. Although fractures initiated on the tension, nonimpact side, butterfly fragments formed on either compression or tension sides. Using newly defined breakaway fragment shape criteria, impact side was estimated with 98% accuracy for both complete and partial butterfly fractures. Furthermore, the results suggest that the impact site is the located on one of the Y-fracture's arms, not the butterfly fragment's center, as previously modeled.
['Reber|Samantha L|SL|', 'Simmons|Tal|T|']
D000818:Animals D001696:Biomechanical Phenomena D005264:Femoral Fractures D018732:Forensic Anthropology D023421:Models, Animal D012756:Sheep D014949:Wounds, Nonpenetrating
injury mechanisms blunt force trauma butterfly fractures fracture production forensic anthropology forensic science