Comparison of cervicovertebral dimensions in Australian Aborigines and Caucasians.

Cervicovertebral dimensions were compared in a group of 30 male and 30 female young adult Australian Aborigines from the Northern Territory, and a control sample consisting of 60 Caucasian dental students from Adelaide, matched for sex and age. Thirty-six variables, 22 cervical and 14 craniofacial, were derived from standardized lateral roentgenograms with the use of a computerized cephalometric system. Vertebral body height and length were significantly greater in Aboriginal males than females for C3 to C7, while dorsal arch height of C1 and C2 displayed the greatest dimensional variability in both sexes. The antero-posterior length of C1, dens height, and body heights of C3 and C4 were significantly shorter in Aborigines than Caucasians for both males and females. Total length of the column from C2 to C6 was approximately 12 per cent shorter in the Aborigines compared with Caucasians. The height of the posterior arch of C1 was significantly correlated with one or both posterior cranial base lengths in Aborigines and Caucasians. Associations were also noted between mandibular lengths and posterior arch heights of the upper two vertebrae. The results confirm and clarify several previous observations on the relative shortness of the cervical spine in Australian Aboriginals. They also indicate some associations between dimensions of the cervical vertebrae and craniofacial lengths, particularly those representing the posterior cranial base and the mandible.