Tracking Rib Deformation Under Anterior Loads Using Computed Tomography Imaging

This paper presents the results of a study to quantify rib deformation under diagonal concentrated (seatbelt-like) anterior loading and distributed (airbag-like) anterior loading as a function of chest deflection using computed tomography (CT) imaging. Three-dimensional measurements were taken using radio-opaque markers installed at three locations (anterior, lateral, posterior) on ribs one through ten bilaterally. Four incremental levels of quasistatic chest deflection were applied, up to a nominal maximum level of approximately 50% of the initial chest depth, and full-thoracic CT scans were obtained at each level of deflection. Four post-mortem human subjects (PMHS) were imaged: two with the concentrated loading condition and two with the distributed condition. The three-dimensional marker displacements were normalized to a 50^th percentile male and used to develop rib deformation trend lines as a function of chest deflection level and anterior loading condition. The trend lines show that deformations were generally largest anteriorly and smallest posteriorly. They also confirm that most rib deformation occurs in the posterior direction.