Forensic application of micro-radiological analysis and 3D-printed vertebrae in a stab wound homicide case

Stab injuries involving the vertebral region are rare and pose significant challenges during forensic autopsy due to the complexity of the surrounding anatomical structures. Radiological techniques, such as post-mortem computed tomography (PMCT) or micro-CT, have shown great potential for detecting and detailing sharp bone lesions. We herein present a fatal case of homicidal stab wound involving the left vertebral artery and the homolateral surface of the axis. PMCT identified a fracture of the left lateral mass of the axis (C2), and micro-CT revealed a cortical discontinuity of the left transverse process of C2, nearly separating the transverse process from the body of the axis. Based on micro-CT data, a 3D model of the first three cervical vertebrae was printed in a clear material on a Formlabs Form 3L printer, and a fit-matching analysis was conducted with two potential weapons. The billhook seized by the Police demonstrated a precise fit with the fracture pattern when its handle was positioned posteriorly, and the tip penetrated laterally in a left-to-right trajectory. In conclusion, to the best of our knowledge, this is the first report of vertebral stab wound analysis using a combined micro-CT and 3D printing approach. Although 3D printing is not yet a fully validated forensic method, and further research is needed for identifying any potential errors occurring during production, segmentation, stereolithography data generation, and post-processing, this report highlights the high potentiality of micro-radiology and 3D printing as promising tools for the morphometric analysis of vertebral injuries.