Erb’s muscular dystrophy [Wilhelm H. Erb] , a form of muscular dystrophy that first affects the shoulder girdle and later often involves the pelvic girdle. It is a progressively disabling disease with onset in childhood or adolescence and is usually inherited as an autosomal-recessive trait. It affects both sexes. In males, differential diagnosis of Erb’s muscular dystrophy and Duchenne’s muscular dystrophy may be difficult. Also called scapulohumeral muscular dystrophy.