Self-contained crash or run-over by a vehicle? Integrating post-mortem CT and kinematic analysis to reconstruct motorcycle accident dynamics

• Forensic experts need strong criteria to distinguish frontal impact from run-over • Integrating forensic pathology, radiology, and kinematic analysis is crucial • Post-mortem CT scans details bone fractures, especially in complex cases • Motorcycle compression can cause crushing injuries, complicating diagnosis Differentiating between primary impact injuries and those caused by a run-over event in motorcycle accidents can be challenging due to the complexity of trauma mechanisms and the lack of standardized diagnostic criteria. This report presents the case of a 57-year-old motorcyclist found deceased following a collision, with initial suspicions raised by surveillance footage suggesting the possibility of a run-over by a passing car. A comprehensive forensic investigation was conducted, including autopsy, post-mortem computed tomography (PMCT), and kinematic analysis, to determine the cause of death and reconstruct the accident dynamics. The PMCT played a pivotal role in accurately documenting complex injury patterns, such as bilateral anterior-posterior fractures of the skull, ribs, and pelvis, which initially suggested a crushing mechanism. However, integration with kinematic findings and circumstantial evidence excluded the involvement of the suspected car. Instead, it was determined that the injuries resulted from compression between the overturned motorcycle and a tree during the collision. This case highlights the indispensable value of PMCT in forensic investigations, particularly in identifying subtle fracture patterns and enhancing injury interpretation. Despite the sensitivity and applicability of PMCT in traffic accidents, there is limited data regarding the interpretation of differential diagnoses between crush injuries and blunt-force impacts in motorcyclists. The systematic use of PMCT, combined with interdisciplinary collaboration between forensic pathologists, radiologists, and kinematic experts, represents a significant advancement in reconstructing complex traffic accidents and reducing uncertainty in medico-legal evaluations.