Ontogenetic perspectives on modern human long bone growth: the humerus

Biological anthropologists routinely infer ancient human behaviour from macroscopic skeletal markers, although the underlying relationship between bone growth and functional adaptation remains complex. To date, few studies have undertaken a microstructural analysis of bone plasticity in relation to ontogeny. The primary aim of this study is to map histological changes within the humerus with age. If the histological changes have a strong correlation with age then it will be possible to produce a regression equation to predict juvenile age-at-death. This is the secondary aim of the study. The final aim is to ascertain how bone robusticity influences bone growth, within age-matched juveniles. A sample of 83 juvenile skeletons from St. Gregory’s Priory, Canterbury were aged using standard methods. One 0.5 cm histological section was removed from the anterior humeral midshaft of each skeleton. Histological slides were prepared using standard methods. The density and morphometrics of primary osteons and secondary osteons were recorded using a high resolution microscope. Results show that primary osteon population density has a strong negative correlation with age (rs = -0.672, N = 83, p < 0.0005). Secondary osteon population density has a strong positive correlation with age (rs = 0.878, N = 83, p < 0.0005). A regression equation to estimate age at death from primary and secondary osteon population density was produced. The equation can be used to estimate juvenile age-at-death, between 0 - 17 years of age, with 86.1% accuracy. In an age matched sub-group robusticity was found to have a negative correlation with secondary osteon population density (rs = -0.642, N = 35, p < 0.001).