Microscopic characterization of longitudinal heat-induced fractures in calcined human remains

Fire is a primary method of corpse destruction, complicating victim identification and the determination of cause and manner of death. This study focuses on the microscopic examination of fracture behavior in osteonal structures, referred to as osteonal damage analysis, to distinguish heat-induced fractures from perimortem and postmortem mechanical fractures. Thin sections of calcined bone were compared with perimortem and postmortem blunt trauma samples to investigate differences in the fracture behavior of osteonal structures. Statistical analysis using a Generalized Linear Mixed Model (GLMM) revealed significant variations (p < 0.05) in fracture patterns. Fractures predominantly crossed osteons, either cutting through the Haversian canal or following the cement line. While significant differences in fracture profiles were found, no pattern was exclusive to any group, with all fracture patterns present across all groups in varying frequencies. Crucially, the findings related to the calcined group suggest, for the first time, that heat-induced longitudinal fractures can intersect the Haversian canals, challenging the longstanding belief that only transverse fractures cross osteons transversely. These findings underscore the complexity of differentiating heat-induced from mechanical fractures and highlight the need for further research. A deeper understanding of osteonal damage is crucial for advancing forensic analysis of burned remains.