The leading cause of death among children is traumatic injury. Injuries in which the head and abdomen are injured account for 40% of the trauma related deaths and isolated thoracic injuries account for 5% of the deaths. The initial motion of the thorax dictates the relative movement of the head and cervical vertebrae. Therefore, it is important to define the properties of the thorax to understand and predict the motion of the head and neck in traumatic injury. Further, pediatric thoracic injuries such as pulmonary contusions have been shown to occur without any rib fracture due to the increased flexibility of the developing rib cage as compared to an adult.

The material properties of the adult rib have been well documented, whereas little information is available for the mechanical properties of the pediatric rib. Currently the biomechanical values used to create the pediatric anthropomorphic testing device (ATD) are obtained from scaling the adult properties purely based on size. Accurate data defining the material properties of the pediatric rib will improve analytical modeling results and provide valuable information for child dummy design.

To date, The Ohio State University Injury Biomechanics Research Laboratory has tested 48 rib specimens from 13 pediatric human subjects with ages ranging from 1 day to 6 years of age. Each rib specimen was tested in three-point bending and analyzed for stiffness, Young’s modulus, peak force and yield stress. These material properties were analyzed both at biological age and at a corrected “age” based on the National Growth Charts. The findings have been compared to published adult rib properties.