Unique Suites of Trabecular Bone Features Characterize Locomotor Behavior in Human and Non-Human Anthropoid Primates

Abstract

Understanding the mechanically-mediated response of trabecular bone to locomotion-specific loading patterns would be of great benefit to comparative mammalian evolutionary morphology. Unfortunately, assessments of the correspondence between individual trabecular bone features and inferred behavior patterns have failed to reveal a strong locomotion-specific signal. This study assesses the relationship between inferred locomotor activity and a suite of trabecular bone structural features that characterize bone architecture. High-resolution computed tomography images were collected from the humeral and femoral heads of 115 individuals from eight anthropoid primate genera (Alouatta, Homo, Macaca, Pan, Papio, Pongo, Trachypithecus, Symphalangus). Discriminant function analyses reveal that subarticular trabecular bone in the femoral and humeral heads is significantly different among most locomotor groups. The results indicate that when a suite of femoral head trabecular features is considered, trabecular number and connectivity density, together with fabric anisotropy and the relative proportion of rods and plates, differentiate locomotor groups reasonably well. A similar, yet weaker, relationship is also evident in the trabecular architecture of the humeral head. The application of this multivariate approach to analyses of trabecular bone morphology in recent and fossil primates may enhance our ability to reconstruct locomotor behavior in the fossil record.

Gracility of the modernHomo sapiensskeleton is the result of decreased biomechanical loading

“…Because the primary goal of the present analysis was to investigate structural differences between the human foragers and agriculturalist groups, and only secondarily to analyze interspecific differences in trabecular bone microstructure, phylogenetic correction was not performed. Recent work has found minimal phylogenetic effects on bone microstructure (66,77).…”

“…Human proximal femora were scanned on the OMNI-X HD600 microcomputed tomography scanner (Varian Medical Systems) at the Center for Quantitative Imaging, Pennsylvania State University. All nonhuman primates included in the study were scanned at the Center for Quantitative Imaging or at the University of Texas at Austin's High-Resolution X-Ray Computed Tomography Facility (18,52,(64)(65)(66). Voxel dimensions ranged from 0.0068 and 0.0687 mm, depending on size of the specimen.…”

“…Voxel dimensions ranged from 0.0068 and 0.0687 mm, depending on size of the specimen. A cubic VOI was defined within each femoral head using Avizo software (FEI Visualization Sciences Group), following previously described methods (18,52,66,67). The center of each VOI was positioned at the center of the femoral head articular surface bounding box, defined as the center of the femoral head in this study.…”

“…The size of each VOI was equal to one-sixth of the superoinferior height of the articular surface. The trabecular bone in each VOI was segmented using an iterative algorithm (68,69) and the 3D trabecular bone structure was quantified using the Scanco image processing language (Scanco Medical) (18,52,66). Six morphometric variables were quantified using standard techniques (18,22,70): BV/TV, Tb.Th, Tb.Sp, Tb.N, DA, and BS/ BV.…”

Lumbar Vertebral Body Bone Microstructural Scaling in Small to Medium‐Sized Strepsirhines

“…Discrete analyses do not consistently distinguish locomotor groups at all sites (e.g., proximal femur in anthropoids) and fail to appreciate the synergy between tissue types and different features contributing to bone strength. Ultimately, to better understand whole bone scaling patterns, integrated analyses including trabecular and cortical bone tissues as well as architectures and tissue density will need to be incorporated (e.g., Ryan and Shaw, 2012) to fully understand interspecific relationships between bone and body mass in the vertebral column.…”