Rheumatoid synovitis of the volar compartment of the wrist joint: its radiological signs and its contribution to wrist and hand deformity.

The radiological signs that suggest involvement of the volar compartments of the wrist include grooving of the scaphoid, pseudocysts of the distal radius, and scaphoid-lunate dissociation. These indicate involvement of the radiocarpal ligamentous support. This leads to loss of stability of the scaphoid, which then goes into a volar-flexed position, contributing to shortening the radial carpal height and favoring rotation of the carpus into supination, radial deviation of the metacarpals, and ulnar drift of the fingers.