Ulnar conduction block at the wrist

Two cases of ulnar nerve lesions at the wrist are reported. The lesions had an acute onset and exclusively impaired the ulnar motor deep branch. The c oexistence of carpal tunnel syndrome in each case allowed an early diagnosi s but was somewhat misleading. In both cases, the use of classic motor and sensory conduction studies did not provide clear abnormalities that would h ave precisely determined the site of the nerve lesion. In both cases, only palmar stimulation of the ulnar motor deep branch showed an important condu ction block. This electrodiagnostic finding showed definitively the site of the ulnar nerve lesion at the wrist and excluded proximal ulnar nerve lesi ons or C8-T1 radiculopathy. In both cases recovery occurred without surgery . (C) 1999 by the American Congress of Rehabilitation Medicine and the Amer ican Academy of Physical Medicine and Rehabilitation.