Location and accumulation of primary head injuries, and prevalence of secondary injuries among neuropathologically examined medico-legal autopsy cases – A comparative study of falls and assaults

Even though traumatic brain injury (TBI) is a major cause of death globally, detailed data on the location and accumulation of primary head injuries, and prevalence of secondary injuries in distinct injury circumstances such as falls and assaults is limited. This study aimed to highlight the differences in injury patterns between falls and assaults among neuropathologically examined medico-legal autopsy cases. Data were collected on a total of 128 cases from the Forensic Medicine Unit, Finnish Institute for Health and Welfare, between the years 2016 and 2022. All cases had suspected or confirmed acute head injuries and underwent a full neuropathological examination. Background and circumstantial variables, as well as the presence of head and brain injuries, were extracted from the medico-legal autopsy case files. Comparative analyses were conducted between assured falls (n = 26) and assaults (n = 23). Any primary head injury was observed in 57.0 % of the full sample; the most common primary injuries were scalp haemorrhage (47.7 %), subarachnoid haemorrhage (SAH) (24.2 %), and diffuse traumatic axonal injury (13.3 %). Assault cases showed a significantly higher prevalence of scalp haemorrhage (82.6 % vs. 46.2 %, p = 0.016) and SAH (52.2 % vs. 11.5 %, p = 0.004) compared to fall cases. In assault cases, the left hemisphere was clearly more frequently affected than the right one (91.3 % vs. 65.2 %). Of secondary injuries, brain oedema was more common in assaults than falls (47.8 % vs. 7.7 %, p = 0.003). In conclusion, this study highlights differences in head and brain injury patterns between falls and assaults. Scalp haemorrhage and SAH are more common in assaults than falls. Assaults appear to lead to a higher frequency and diversity of injuries, particularly in the left hemisphere.