Internal Bone Structure and Orientation in the Browridge of Homo, Pan, Gorilla, Papio, and Cebus

Abstract

Assessing the variation of the internal bone structure, anisotropy and orientation in the browridge across regions and species can aid in our understanding of craniofacial adaptation. Also, quantifying species and region specific variation may serve to improve the accuracy of finite element models. In this study, μCT was used to determine the structural properties, degree of anisotropy (DA) and primary trabecular orientation in 3 equally divided browridge regions of 8 Homo, 5 Pan, 7 Cebus, 4 Papio, and 1 Gorilla. Both bone volume fraction (BVF) and degree of anisotropy (DA) differed significantly by species (Kruskal‐Wallis Test, p<0.001 and p<0.015, respectively). Most regions across species showed orthotropy. In all species and regions, trabeculae tend to show less variability in orientation across transverse and coronal planes. Orientations in the sagittal plane instead show higher variability across individuals. The results suggest that BVF, DA and orientation of trabecular‐like bone within the supraorbital region may be reflective of feeding strategies and that characterization of subcortical structure in craniofacial regions may improve finite element models. Additional study of trabecular bone orientation within zygomatic regions is ongoing to examine how trabecular bone orientation and DA differ across the entire craniofacial region in these species.Grant Funding Source: Science Foundation Physical Anthropology HOMINID program (NSF BCS 0725141)