AP view of the right wrist, and extension and flexion lateral views
of the cervical spine
Rheumatoid arthritis (RA) is an inflammatory arthropathy, characterized by the production of inflammatory pannus, which in turn leads to osseous erosions. In the wrist, RA tends to develop in a pancarpal distribution, as opposed to the radiocarpal distribution of calcium pyrophosphate deposition disease (CPPD) or the 1st carpometacarpal joint/scaphotrapezial distribution of osteoarthritis (OA).
When RA involves the cervical spine, it may involve the facet joints or certain ligaments, notably the transverse ligament of the first cervical body (C1). If this ligament is indeed involved to a large enough extent, it may rupture, which allows anterior translation of C1 with respect to C2, widening the predental space. This space is normally no larger than 3 mm in adults, and up to 4 mm in children.
AP view of the right wrist, and extension and flexion lateral views
of the cervical spine
Click the images for a more detailed view.