Structural and Material Characteristics of the Pediatric Thoracic Cage and Their Relationship to Age-Related Changes in Thoracic Response

Co-Principal Investigator: Sriram Balasubramanian, PhD, Children's Hospital of Philadelphia

Below is an executive summary of this project. Please note that this summary describes results and interpretation that may not be final. Final interpretation of results will be in the peer-reviewed literature.


Today’s child crash test dummies, also known as anthropomorphic test devices (ATDs), are basically smaller versions of adult-sized dummies with little consideration for differences in age-related body composition. This research study contributes to delivering the basic data needed to improve specific body regions of the pediatric ATDs and to develop innovative restraint products to make vehicles safer for children in the future. These advances will help save children’s lives, prevent injuries, and reduce the economic cost of crashes involving child passengers.

The biofidelity of the ATD chest is critical because it is one of the primary load paths of a seat belt or child restraint harness. As children age, the ribs and sternum structurally change; bones fuse, and the ribs angle downward and twist. This study quantified the three-dimensional geometric characteristics of the pediatric thoracic cage for males ages 1, 3, 6 ,10, and 18 years using chest CT scans collected from CHOP patients via specialized software to visualize, segment and render 3D images of the pediatric torso. Based on these reconstructions, a custom code was created to compute several geometric parameters of the thoracic cage.

Age-specific geometric differences were observed in the pediatric thoracic cage structure for several geometric parameters, including rib length and lateral rib angle. The researchers also found that, on average, the apparent curvature of the thorax tends to decrease with age with the shape of the chest being more elliptical and less circular with age. In addition to helping to create more accurate child crash test dummies, this data can be applied to a wide range of technology applications to improve child safety, as well as medical training, including simulation tools and medical implant design and development. 

IAB Mentors

Christina Mullen, State Farm Mutual Automobile Insurance Company; Steve Ridella, National Highway Traffic Safety Administration; Steve Rouhana, Ford Motor Co.