Structural analyses of the developing human postcranial skeleton using high‐resolution CT

Abstract

The initiation and maturation of human walking combined with increasing body mass during ontogeny contribute to major changes in the mechanical loading of the postcranial skeleton during childhood and adolescence. Quantitatively tracking associated morphological changes provides important insights into functional bone adaptation and the evolutionary morphological changes associated with the evolution of upright bipedal walking in hominins. MicroCT is a powerful tool for analyses of bone development that allows non‐destructive access to internal bone structure. This study uses microCT to examine the developmental trajectories of cortical and trabecular bone structure in the postcranial skeleton of humans from birth to adulthood. MicroCT scans were collected for the femur, tibia, humerus, and lumbar vertebrae of 70 juvenile and adult humans with voxel sizes between 0.017 to 0.113 mm. Cortical bone follows broadly similar growth trajectories into adulthood in the femur and tibia, but not in the humerus, while trabecular bone displays a more complex pattern. Most trabecular variables follow unique trajectories reflecting localized bone growth and (re)modeling processes that approach adult values after about 10 years of age. While clearly interrelated, cortical and trabecular bone follow distinct growth trajectories likely due at least in part to divergent biomechanical stimuli.