[Paralysis of the ulnar nerve caused by osteochondromatosis]

Synovial osteochondromatosis is a rare pathology (5% according to Mumenthaler, 1961) producing a compression of the ulnar nerve in the elbow and/or the wrist. The authors describe 4 cases of this pathology (3 of the elbow and 1 of the wrist) analysing its etiology and, in particular, the predisposition of the synovial membrane.