Abstract
We present a unique variant of C1 fracture, which, at the best of our knowledge, has never been previously reported. This lesion consists in a lateral mass atlas fracture with a longitudinal separation of the transverse ligament that remains functionally preserved. We considered this lesion to be stable and treated the patient conservatively with good recovery. Even if many classifications of atlas fractures have been proposed, none of them ever described this uncommon variant. We debate about biomechanical aspects and therapeutic implication of the reported case.