Biomechanical Response Targets of Adult Human Ribs in Frontal Impacts

Thorax injuries mainly due to rib fractures have been associated with high rates of morbidity and mortality in motor vehicle crashes. Thoracic biomechanics has been studied extensively, but there are no robust biomechanical response targets for ribs that consider age, sex, body size, and vulnerability factors. The objective of this study was to generate biomechanical targets for human rib response with respect to age, sex, and body size. Two-hundred sixty-one ribs from 171 individuals were dynamically loaded to failure in anterior-posterior bending. Force and displacement at the time of fracture in young adults were greater than in older adults (p < 0.0001). Sex differences were found in those over 40 years old (p < 0.0001). Fracture force from 5th percentile female ribs was lower than 50th and 95th male (p < 0.005). Vulnerable ribs were successfully identified by examining the percentile of both force and displacement at the time of fracture in the proposed samples. The biomechanical targets generated in this study will have useful applications to computational thorax and rib models to aid in injury prevention measures.