As the shape of a normal vertebra differs significantly by population, sex, and age, defining what is normal within each population is essential in order to form a more sophisticated understanding of both abnormal and normal vertebrae. Not only does a populational profile of a healthy vertebra allow for the isolation of abnormal vertebrae as representative of potential osteoporotic fracture, it also reveals differences in vertebral shapes in upper, mid, and lower thoracic vertebrae, which reflect varying mechanical stress experienced in each section. Such stresses are determined by biological variance as well as cultural practices, including division of labor along sex and age boundaries.
This study examines normal variation in the centrum heights of 187 thoracic vertebrae from 33 adult individuals in the prehistoric Northeastern Ohio Grantham skeletal population; and 396 thoracic vertebrae from 37 adult individuals in the prehistoric Southwestern Ohio SunWatch skeletal population. Disparities in vertebral shape along the thoracic portion of the vertebral column and consistent distinctions between normality in sex and age groups were recorded within and between each population. Differences in type and degree of lifetime mechanical stress and additional pathological spinal conditions resulted in normal vertebral morphology and age-related change which varied between Grantham and SunWatch. In both populations individuals with potential osteoporotic fractures were found. The appearance of age-related deformation differed between the two prehistoric samples in this study compared to similar work done with modern populations. A populational survey of normality is essential in understanding how biological tendencies and cultural practices have shaped aging in human bodies.