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Motor vehicle accidents are the leading cause of death of people between one and thirty-four years of age in the U.S., and head trauma is a significant lethal injury in such cases. During a motor vehicle crash, the head often experiences blunt force trauma from impacts with seat backs, steering wheels, windows, and dashes. The resulting injuries can cause skull fractures, concussions, bleeding and swelling of the brain. Crash test dummies and finite element models are often used to study the nature and likelihood of injury during a crash, but these are currently based on scaled versions of a standard, 50th percentile male. This approach fails to accurately capture the size and shape variation in even the adult population, but may be especially inappropriate for modeling pediatric head injuries where, for instance, infants have fontanelles and reduced bone structure. In this presentation, an approach for modification of a finite element model of the human head based on 50th percentile male dimensions and representing the skull, brain, dura/CSF layer, and Falx Celebri, that will incorporate the anatomical and nonlinear morphological changes observed in pediatric skulls during ontogeny. Using 96 CT scans of normal pediatric skulls, landmark coordinate points are identified to map the changes in skull shape and size as aging occurs. The pediatric skull changes rapidly in size and shape during the first two years of age. Using this information, a pediatric finite element head model will be created, using parametric mesh generation software, to measure head injury in children in a motor vehicle crash.

To fully understand the effects of aging on the integrity of the normal skeleton, detailed geometric models are needed to complement material property data. The purpose of this research is to develop a predictive model for age-related changes in rib-cage geometry using the generalized Procrustes approach, an advanced method of shape analysis. This predictive model is coupled with the finite element method to isolate the effects age-related size and shape change have on the structural response of the rib cage. Using a relatively small sample set (n = 12), trends in the age-related size and shape change of the human thorax consistent with clinical observations are identified. Finite element models constructed from landmark datasets generated via the generalized Procrustes approach demonstrate a decrease with age in the energy absorbing capacity of the thorax during a blunt impact.