Variation of bilateral transverse ligament tubercles with age and gender in a large series of subjects on multidetector computed tomography

Background: The transverse ligament tubercles play an important role in maintaining the stability of upper cervical spine, but the variation of these tubercles with aging has not been studied systematically. Purpose: To evaluate the variation of the height of the transverse ligament tubercles with respect to age and gender, and assess side-to-side differences on multidetector computed tomography (MDCT). Material and Methods: A consecutive series of 291 Chinese patients undergoing a head or neck MDCTwere divided into eight age groups. The bony anatomy of the atlas was displayed symmetrically by aligning the axial plane and the mean height of bilateral transverse ligament tubercles was measured. The height was correlated with age and gender and sideto-side differences were analyzed. Finally, the inter-observer performance was assessed. Results: No transverse ligament tubercles were seen in 51 cases (17.5%, 51/291) and unilateral transverse ligament tubercles were seen in two cases (0.7%, 2/291). Bilateral transverse ligament tubercles were observed in 238 cases (81.8%, 238/291). The average height of the left and right tubercles were 2.68=1.58mm and 2.68=1.54 mm, respectively, with no significant side-to-side differences (t0.061, P>0.05). The height was also similar in both genders (left: t0.497, P>0.05, right: t0.730, P>0.05). The height increased linearly with age (left: r0.513, P<0.05, right: r0.516, P<0.05). The inter-observer reliability was excellent. Conclusion: The height of the transverse ligament tubercles on MDCT linearly increases with increasing age with no significant differences among the genders or the side measured.