Observation of a patient found in coma in consequence of a cerebral hemorrhage. The presence of an amyotrophy of the left hand, type Aran-Duchenne and of an osteo-arthropathy at the elbow, directed the diagnosis to a syringomyelia. After discussing the differential diagnosis between nervous leprosy and tabes, the AA. refer to the pathologic findings: a cavity located in the left half of the spinal cord, essentialy extending to the basis of the posterior and anterior cornu, to the vegetative centers of the intermedio-lateral zone and to the posterior cornu in almost the entire area. Commenting the observation, the AA. emphasize: 1) the value of both mentioned manifestations, Aran-Duchenne hand and osteo-arthropathy, in the diagnosis of syringomyelia; 2) the interest of the anatomic verifications that represent a contribution to the study of the pathogenesis of neuropatic osteo-arthroses. Such verifications, according to the AA., prove Alajouanine's pathogenic conception, which claims that the intramedullary sympathetic lesions are responsable for the osteo-articular disorders in tabes and syringomyelia.