Sacralization is not associated with elongated cervical costal process and cervical rib.

Cervical rib/elongated costal process of the seventh cervical vertebra and sacralization of a lumbar vertebra are associated with clinical problems-neurological, vascular, and obstetrical. A previous study reported an association between these morphologies, and suggested that clinicians use presence of one trait to predict presence of the other. This study tested three hypotheses from this association: costal process length among individuals with sacralization differs from that among individuals without sacralization for: (1) only the seventh cervical vertebra, (2) only transitional presacral vertebrae-seventh cervical, twelfth thoracic, and fifth lumbar, and (3) presacral vertebrae in general. Skeletons of 961 individuals between ages 20 and 49 years from the United States were surveyed for sacralization. Costal process length was measured on 100 individuals with sacralization and 184 without sacralization for cervical vertebrae 3 to 7, thoracic vertebrae 11 and 12, and all lumbar vertebrae. Cervical rib was evaluated for 102 individuals with sacralization and 472 without sacralization. Results showed that 11% (105 of 961) of individuals have sacralization. Compared to individuals without sacralization, those with sacralization: (1) have significantly longer costal process for the last lumbar vertebra, but are nonsignificantly different for costal process lengths of other vertebrae, (2) are nonsignificantly different in prevalence of cervical rib-2.9% with sacralization and 0.4% without sacralization, and (3) are significantly more likely to have an extra presacral vertebra. Clinically, results suggest that sacralization is not a predicate for either cervical rib or elongated costal process of the seventh cervical vertebra.