[The lateral atlantoaxial joint involvement in the rheumatoid arthritis. Report of ten cases and review (author's transl)].

An analysis of ten recent observations of lateral arthritis of C1-C2 during the course of rheumatoïd arthritis. This lesion, which is not rare, has charactéristic symptoms: localized pain together with occipital (Arnold's) neuralgia and specific blocking of head rotation towards the afflicted side. Frontal per-oral radiography shows joint line lesions most often unilateral, and a displacement of C1 towards the non afflicted side with pseudoinclination of the odontoïd process towards the afflicted side. Sometime more destructive lesions of the lateral masses of the atlas give them a triangular form and this may result eventually in an upwards "vertical" displacement of the odontoïd. The pain usually subsides in a few weeks after a conservative treatment with or without temporary immobilisation by a light removable cervical collar but the loss of the homolateral rotation of the head persists. Besides occipital (Arnold's) neuralgia, there seems to be no other neurologic complications; if they follow, it is due to an associated anteroposterior displacement.