Abstract This case report details diagnosis of an apparent compression fracture of the lateral mass of the atlas vertebra with an associated avulsion fracture of the medial portion of the lateral mass. Congenital abnormalities of the posterior arches of both atlas and axis were also noted. The patient, a 59-year-old Caucasian male had two previous incidents of severe cervico-cranial trauma but was asymptomatic on presentation though demonstrating reduced cervical ranges of motion. Fractures of the atlas are considered rare, and isolated fractures of the lateral mass have only been reported on seven previous occasions, seldom being visualised on plain film radiographs. None of these cases involve a compression fracture of the lateral mass which may therefore be regarded as an unique radiological finding.