Fusion of the lateral joints in fixed atlantoaxial dislocation: a computed tomography demonstration

Fixed atlantoaxial dislocation is a well-known phenomenon that may partially account for the discrepancy between the radiographic and neurologic abnormalities seen in rheumatoid arthritis of the craniocervical region. In this care report, "arthritis rigidity" is demonstrated by computed tomography to be due to fusion of the occipitoatlantoaxial complex, following erosion and disruption of these joints by rheumatoid disease.