Quantifying Micro-crack Length on Bone Fracture Surfaces

This study determined that the mean length of microcracks on fractured cortical bone surfaces (in a porcine experimental model) inflicted by standardized impact progressively increased from the order of 180 µm to 375 µm during soft tissue decomposition, over 140 days in situ, equating to 638 cooling degree days in total. The morphology of these micro-cracks altered from initial multiple intersecting cracks, with an apparent prevalence of three micro-cracks emanating from a central point at 0-28 cumulative cooling degree days to longer, linear cracks, appearing to track lamellae as soft tissue decomposition progressed. There were statistically significant increases in micro-crack length between fracture surfaces of known perimortem fractures (mean of 61.04µm) and those due to known taphonomic damage (mean of 93.23 µm) on comparative human bone samples, from the Nubian and Medieval skeletal collections of the Natural History Museum, London.