Morphometry of the cervical and lumbar vertebrae in two caucasian ethnic groups.

We performed a morphometric study of the low cervical and all lumbar vertebrae of 111 Caucasian skeletons, 63 Italians and 58 Asiatic Indians. In the Italian group, the mean dimension of the spinal canal as well as those of the vertebral body were superior at all cervical levels to those of the Indian group. The lower normal limit of the midsagittal diameter was 11.1 mm in the Italian series and 10.3 mm in the Indians. In 8% of the Italians and 12% of the Indians this measurement was from 10,3 to 11 mm, and 9.4 to 10 mm respectively. The interpenduncolar diameter of the canal was less at all levels than the saggital diameter. In both groups, the sagittal diameter and the transverse width of the body increased progressively from C3 to C7; the minimum body height was found at C5. The lowest normal limits of the midsagittal diameters of the lumbar spinal canal were 12,6 mm in the Italian skeletons and 11,5 mm in the Indian senes. The midsagittal diameters of the canal measured, at one or more levels, 10 .1 - 10.8 mm in 5% of the Italian skeletons and 9.0 - 10 .5 mm in 10% of the Indian skeletons. In most vertebrae with midsagittal dimension of the canal less than 11.5 mm, the width of the recesses was at or below the lower limits of normal, The cervical spines in which the A. P. diameter of the canal was below the normal limit were the same as those in which the lumbar spinal canal showed restriction of the sagittal diameter below normal limits at one or more levels. This study indicates that the dimension of the spinal canal vary significantly in different ethnic groups of the same race. It contradicts the opinion that a sagittal diameter less than 12 mm has to be considered pathologic. It also indicates that subjects with a narrow cervical spinal canal are more likely to have a narrow lumbar canal and vice versa.