The radiology of rheumatoid involvement of the cervical spine.

The radiological features of cervical spine involvement in rheumatoid arthritis are described. These include atlanto-axial subluxation, in both the horizontal and vertical planes, sub-axial dislocation, erosions, and vertebral end plate sclerosis. Detailed radiological investigation, using inclined plane radiography, auto-tomography, tomography, and myelography may all be required to demonstrate the abnormalities. Disorders of mobility can only be assessed with dynamic views and fluoroscopy and the mechanics of these derangements vary depending on the type of subluxation encountered. The cumulative effects of the lesions conform to certain characteristic patterns and include marked reduction of neck height, disorders of mobility, and changes in the capacity of the spinal canal. The discrepancy between these changes and the clinical and neurological findings is discussed.