Wet bone characteristics persist in buried bone after 10 weeks: implications for forensic anthropology

Assessing the timing of skeletal trauma significantly impacts the reconstruction of events surrounding death and deposition in forensic cases. However, there are no absolute time frames in which the characteristics of wet bone (peri-mortem) fractures transition to dry (post-mortem) fractures. The aim of this study was to attempt to identify a point within the post-mortem interval in which the characteristics of bone change from wet to dry bone properties. A total of 32 deer ribs were placed in a laboratory burial environment and a set of three were fractured with blunt force trauma every week during a ten-week period. All samples and the inflicted trauma effects were documented and analysed by macroscopic observation, scanning electron microscope (SEM) analysis, thermal analysis, biomechanical analysis, and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR). No significant difference was found in the macroscopic, microscopic, thermal, and biomechanical analyses of the trauma inflicted over the 10-week period. A significant difference was only found in the carbonate-to-phosphate ratio in analytical chemistry. The results suggest that interpreting wet bone characteristics in forensic anthropology as having been inflicted during the peri-mortem period (around the time of death) should also consider that these, in fact, could be inflicted well after death (post-mortem) as wet bone properties as this study has shown persist at least 10 weeks after death in a burial environment.