Quantifying trabecular orientation in the pelvic cancellous bone of modern humans, chimpanzees, and the Kebara 2 Neanderthal

The adaptive nature of bone lies in its ability to respond to the environment by conforming and reshaping itself constantly to accommodate life‐time stresses experienced throughout daily activities. In order to keep strains within the bone as uniform and isotropic as possible, the trabecular orientation is determined by forces acting on the bone through adaptive remodeling. Hence, the preserved structure of bones may contain direct information about the forces they may have undergone. Some authors (Correnti [1952], Atti Acc Naz Lincei 12:518–523, [1955] Riv Antrop 42:289–336; Macchiarelli et al. [1999] J Hum Evol 36:211–232, [2001] Cambridge, UK: Cambridge University Press) have described in detail the trabecular systems of the hip bone in different primate species and have identified a gait‐related system above the acetabulum with substantial differences across species (Macchiarelli et al. [1999]; Rook et al. [1999] Proc Natl Acad Sci USA 96:8875–8879). The aim of this study was to quantify trabecular orientation above the acetabulum to test the hypothesis that hominoid biomechanical behavior is recorded in the cancellous bone. The pelvic bones of 23 archaeological adult modern humans (12 females, 11 males), 20 adult Pan troglodytes (10 females, 10 males), and one adult male Neanderthal were radiographed and digitized. Fast Fourier transforms (FFTs) of the regions of interest in the corpus of the ilium were performed, with the angular distribution of the trabeculae quantified. All species displayed a constant and periodic orthogonal arrangement in the trabeculae with differences in the pattern of dominance between the arcades oriented along the 0° or the 90° axes. The variation in the FFT spectrum between species is discussed in the light of distinctive biomechanical features. Am. J. Hum. Biol. 15:647–661, 2003. © 2003 Wiley‐Liss, Inc.