A case is reported of a left carpometacarpal dislocation with medical displacement of the fifth metacarpal and volar displacement of the fourth, producing an ulnan-nerve motor deficit. The patient was seen more than one month after the injury. He was treated with neurolysis and open reduction of the dislocations and arthrodesis of the fourth and fifth carpometacarpal joints. He had complete return of ulnar-nerve function and was able to resume his musical career as a violinist.