The posteriorly tilted dens. A normal variation mimicking a fractured dens.
The normal dens occasionally can be posteriorly tilted and in such cases, can mimic a fractured, posteriorly tilted, dens. Differentiation of the two conditions depends on: [1] knowledge that this normal variation of the dens occurs, and [2] demonstrating that no fracture exists. In many cases, this latter determination can be accomplished on plain films, but in other cases, laminography is required.
D001368:Axis, Cervical Vertebra / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D050723:Fractures, Bone / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D011859:Radiography; D013124:Spinal Injuries / Q000175:diagnosis* / Q000000981:diagnostic imaging