Structural analysis of human rib fracture and implications for forensic interpretation

Patterns of rib fractures are of significant clinical and forensic interest. Linking patterns of rib fracture with specific physical events provides a foundation for understanding the nature of traumatic events that are associated with rib fracture in forensic contexts. In this study, isolated human ribs (n = 8) were end-loaded to failure to investigate: (i) local deformations (bone strain) prior to and during structural failure, (ii) location of ultimate failure, and (iii) fracture mode. Structural properties of ribs were used to calculate theoretical stresses to determine whether such calculations could be used to predict site of fracture. Ribs fractured on the sternal side of midshaft in all experiments, but mode of failure varied with transverse, buckle, spiral, and "butterfly" fractures observed. Comparison of calculated stress with observed strain values suggest that experimental, rather than theoretical, approaches will be most productive in furthering understanding rib fracture in forensic contexts.