Structure
The transverse ligament of the atlas is a strong horizontal band that extends across the atlantal ring between its two lateral masses. Its anterior aspect is in contact with the posterior aspect of the dens. Together with the longitudinal bands, it forms the cruciate ligament of the atlas.
It is primarily made up of interwoven collagenous fibers that lace across each other, which results in the central thickening. The overall shape of the ligament is concave anteriorly and convex posteriorly due to the force applied to keep the dens in position. It splits the vertebral canal into an anterior and posterior portion, of which the latter accounts for nearly two thirds of the space.
The anterior aspect of the transverse ligament is lined by articular cartilage, where it is contact with a small facet on the posterior aspect of the dens.
Longitudinal fibers are given off medially at the upper and lower borders of the ligament, which attached to the base of the occipital bone and body of the axis, respectively.
Function
The transverse ligament of the atlas preserves the position of the dens against the anterior arch of the atlas, preventing its displacement. It is the strongest ligament in terms of maintaining stability of the atlantoaxial joint (Offiah & Day, 2017).
List of Clinical Correlates
—Bony avulsion
—Jefferson fracture
References
Offiah, C. E. & Day, E. (2017) The craniocervical junction: embryology, anatomy, biomechanics and imaging in blunt trauma. Insights Imaging, 8(1), 29-47.
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Joint Ligament
Entheseal structures are widely located throughout the body and are represented by the interface between bone and several tissues including tendon, joint capsules and ligaments.
