A THREE-DIMENSIONAL DIGITAL MICROSCOPIC INVESTIGATION OF ENTHESEAL CHANGES AS SKELETAL ACTIVITY MARKERS

The current paper explores the effectiveness of entheseal changes as skeletal activity markers by testing the correlation between such changes and cross-sectional geometric (CSG) properties while controlling for the effect of age and body size. The originality of the paper lies in capturing entheseal changes in a continuous quantitative manner using 3D microscopy. Roughness and bone resorption were recorded on zone 1 and 2 of three humeral entheses (subscapularis, supraspinatus, infraspinatus) in a documented sample of 29 male skeletons. Our analysis found that merely 5.91% of the partial correlations between entheseal changes and CSG properties were statistically significant. In addition, two unexpected patterns were identified, namely a higher number of significant correlations on the left side entheses compared to the right side ones and a higher number of correlations between minimum roughness and CSG properties compared to mean and maximum roughness. These patterns are the inverse of what we would expect if activity had exerted an important effect on entheseal change expression. Therefore, they support the lack of association between entheseal changes and habitual activity, even though various factors potentially affecting the above results are discussed.