Beware of the ulno-palmar distal radial fragment.

Five patients sustained isolated fractures of the ulnopalmar rim of the distal radius. In three cases the fragment was small and was classed as an avulsion fracture of the short radiolunate ligament. Palmar wrist subluxation occurred in all cases, four during treatment in a cast or splint. The ulnopalmar rim of the distal radius contributes to the stability of the radiocarpal joint and fractures in this region merit particular attention.