Posterior atlanto-axial dislocation in rheumatoid arthritis.

Seven patients with rheumatoid arthritis and posterior atlanto-axial dislocation are presented. The patients were elderly women who had suffered with the disease a long time. In all cases earlier cervical radiographs were available, excluding any predisposing congenital anomaly. Fracture and arthritic destruction of the dens, of parts of the body of the axis, or of the anterior arch of the atlas proved to be predisposing factors of the lesion.