[Chronic distal spinal amyotrophy localized to the both upper limbs (O'Sullivan and McLeod type)]

A case of sporadic spinal muscular atrophy affecting the upper limbs and with a chronic course over 19 years is reported, features of the affection being similar to the rare cases reported in the literature. Distinguishing aspects of these cases are those of a particular topographical form of chronic spinal muscular atrophies: onset in adolescents or young adults, symmetrical weakness and atrophy of the small muscles of the hands sometimes extending to the forearms, a progressive and slow course, absence of sensory or pyramidal signs, normal findings on cervical cord examinations neurogenic electromyogram recordings and normal nerve conduction rates.