Forensic assessment of single stab injuries to the trunk

Introduction
Forensic pathologists are frequently confronted with questions about the likelihood that an injury is inflicted by an assault or is self-inflicted. However, little is known of epidemiological variables applicable to differentiate between homicides and suicides in deaths caused by single stab injuries to the trunk.

Method
Using the Swedish forensic autopsy register we identified 94 homicides and 45 suicides between 2010 and 2021 that died following a single stab injury to the trunk. We extracted characteristics from the cases and performed statistical analyses using Mann-Whitney U and Chi-square test.

Result
Victims of homicides were younger than suicide victims (median age 33 years vs. 52 years, p < 0.05), and males were in majority in both groups (93% vs. 82%). Some homicidal stab wounds were placed on the posterior (12%) and axillar trunk (11%) unlike the suicidal stabs which were all placed on the anterior trunk. Most stab wounds of all examinations were placed on the left side of the anterior thorax (60%). In suicides, single stab injuries to the heart were more common than in homicides (67% vs. 48%, p < 0.05). Vasculature injuries were more common in homicides (51% vs. 9%, p < 0.05).

Discussion
The epidemiological variables could be used as a tool when assessing the manner of death in single stabs. Further research on variables associated with manner of death are needed and we suggest also including surviving victims in such analyses.