What impact does the widening of the atlantodens interval (on x-rays) and avulsion of transverse atlantal ligament (on CT) have on management?
This fracture is considered by most to be unstable and requires either halo brace immobilisation or internal fixation.
What is the typical mechanism of injury?
Axial loading (e.g. diving head first into shallow water).
CT through C1 confirms the plain film findings. Two fractures are identified: on the right through the lateral aspect of the posterior arch; on the left through the lateral aspect of the anterior arch. A further fracture fragment is noted posterior to the dens (which appears normal), representing an avulsion fracture of the transverse atlantal ligament from the right lateral mass of C1.