Fractures of the C-1 vertebra: report of two cases documented with computed tomography.

Two cases of vertical fractures through the anterior arch of C-1 vertebrae are described. One was associated with an additional fracture through the posterior arch on the opposite side in the region of the vertebral artery sulcus, and the other with an additional horizontal fracture through the anterior arch. Both patients were neurologically asymptomatic. Diagnosis was made by computed tomography.