Entheseal changes in an ancient Egyptian skeletal collection

The purpose of this study is to examine the effects of age and sex on entheseal changes, as well as test for asymmetry in an ancient Egyptian skeletal collection. Entheseal changes refer to the morphological changes that occur on the bone surface where tendons and ligaments attach. Such morphological changes have been widely considered to reflect past activity patterns. However, recent bioarchaeological and biomedical research has shown biological factors such as age, sex, and body size to be significantly correlated with various types of entheseal change (Henderson et al. 2013 2017 Wilczak 1998; Benjamin et al. 2008 , 2009; Foster et al. 2014). This study utilizes the new Coimbra method (Henderson et al. 2013, 2015) to score and record entheseal changes at five fibrocartilaginous entheses: infra- and supra-spinatus, subscapularis insertion, common flexor origin, common extensor origin, and biceps brachii insertion. The results show bone formation tends to increase with age in males. Erosion tends to increase in females, particularly after age 50 with weaker age trends evident in males. Conversely, there was a slight tendency for fine porosity to be more frequent in individuals thirty years and younger. There was a lack of asymmetry observed within this sample, which argues against the notion that entheseal changes result from habitual mechanical stress. Within this relatively gracile population, there was significant sexual dimorphism in two humeral measurements: the vertical head diameter, and distal articular breadth. Further research is suggested to examine differences between socio-cultural classes, effects of pathological conditions, and to validate the reported impacts of biological factors like age and sex using a larger Egyptian sample.