Utility of osteon circularity for determining species and interpreting load history in primates and nonprimates

• Published in: American journal of physical anthropology 2017-04, Vol.162 (4), p.657-681
• Main Authors: Keenan, Kendra E., Mears, Chad S., Skedros, John G.
• Format: Article
• Language: English
• Subjects: Anatomy, Cross-Sectional; Animals; bone; bone adaptation; Deer; Diaphyses - anatomy & histology; Diaphyses - physiology; Femur - anatomy & histology; Femur - physiology; haversian system; Haversian System - anatomy & histology; Haversian System - physiology; Humans; osteon area; osteon circularity; Pan troglodytes; Sheep; Species Specificity; Tibia - anatomy & histology; Tibia - physiology; Weight-Bearing - physiology
• ISSN: 0002-9483; 1096-8644; 2692-7691
• DOI: 10.1002/ajpa.23154

Objectives Histomorphological analyses of bones are used to estimate an individual's chronological age, interpret a bone's load history, and differentiate species. Among various histomorphological characteristics that can influence mechanical properties of cortical bone, secondary osteon (Haversian system) population density and predominant collagen fiber orientation are particularly important. Cross‐sectional shape characteristics of secondary osteons (On.Cr = osteon circularity, On.El = osteon ellipticality) are considered helpful in these contexts, but more robust proof is needed. We sought to determine if variations in osteon shape characteristics are sufficient for accurately differentiating species, load‐complexity categories, and regional habitual strain‐mode distributions (e.g., tension vs. compression regions). Materials and Methods Circularly polarized light images were obtained from 100‐micron transverse sections from diaphyses of adult deer calcanei; sheep calcanei, radii, and tibiae; equine calcanei, radii, and third metacarpals (MC3s); chimpanzee femora; and human femora and fibulae. Osteon cross‐sectional area (On.Ar), On.Cr, and On.El were quantified indiscriminately and in the contexts of load‐complexity and regional strain‐mode distributions. Results On.Cr and On.El, when examined independently in terms of all data, or mean (nested) data, for each bone, exceeded 80% accuracy in the inter‐species comparisons only with respect to distinguishing humans from nonhumans. Correct classification among the nonhuman species was