Sex differences in activity-related osseous change in the spine and the gendered division of labor at Ensay and Wharram Percy, UK.

Sex differences in the distribution of vertebral degenerative and plastic change were examined and compared within and between samples of 51 individuals from the historically and ethnographically documented 16th-19th century site of Ensay, the Outer Hebrides, and 59 individuals from the medieval site of Wharram Percy, the Yorkshire Wolds. Both populations have a known gendered division of labor between males and females and known activity-related stresses on the spine. Osseous changes normally associated with degenerative joint disease (osteoarthritis) of the apophyseal facets and osteophytosis of the vertebral bodies were scored and reported separately. Inter- and intrasite differences were found in the frequency and distribution of osseous change down the spine. Overall, the Ensay sample was more highly stressed than that from Wharram Percy. Furthermore, differences between males and females at Ensay could be identified as relating to different types of activities. Distinctions between males and females at Wharram Percy were less marked, suggesting broadly similar lifestyles. These results accorded with expectations regarding contrasting levels of activity-related stress at the two sites and the division of labor between males and females. In particular, the prevalence and distribution of facet remodeling, facet sclerosis/eburnation, and osteophytosis in Ensay females could be related to load-bearing using creels (a form of basket), which disrupted "normal" patterns of osseous change along the spine. Importantly, morphologically distinct osseous modifications recorded on the apophyseal facets produced dissimilar distributions, suggesting that they may have different etiologies. These results highlight the need for a high degree of discrimination in recording, analyzing, and exploring activity-related osseous change. Copyright 2000 Wiley-Liss, Inc.