Sagittal clefting of the body and other vertebral developmental errors in Canadian Inuit skeletons

The objective of this study was to determine the expression, distribution in the column, and overall frequency of sagittal clefting of the vertebral body in the skeletons of two Canadian Inuit groups. One group, referred to as Thule-Historic, lived along the coast northwest of Hudson Bay, while the other, known as the Sadlermiut, were limited to Southampton Island and Coats Island north of Hudson Bay. The Thule-Historic people are thought to be the ancestors of the present-day Inuit of this region, whereas the much smaller, relatively isolated Sadlermiut became extinct during the winter of 1902-1903. The sagittal clefting results were also compared with those obtained for two other vertebral developmental problems, segmentation error and spina bifida. Sagittal clefting was found to occur with high frequency in the two Inuit series, especially in the region T6-T10. Segmentation errors were found to occur in approximately the same region of the column, while spina bifida produced a completely different pattern, occurring primarily at T11 and S1. The T11 involvement is limited to females, while S1 involvement occurs primarily in males. Sagittal clefting and spina bifida occur in the same individual more frequently than sagittal clefting and segmentation error. Possibly reflecting the smaller population size and isolated location of the Sadlermiut, sagittal clefting was found with greater frequency and intensity in the skeletons of this group than in those of the Thule-Historic Inuit. Am J Phys Anthropol, 2003.