Deformities of the hands and feet in Parkinsonism and their reversibility by operation.

Charcot (1877) described some aspects of the typical deformities of the hands and feet seen in Parkinson's disease. He likened the deformity of the hands to that sometimes observed in chronic progressive rheumatism. He said that the differential diagnosis is usually made with ease, because in cases of Parkinsonism 'there is found neither the articular tumefaction and stiffness, nor the osseous deposits and cracking sounds observed in nodose rheumatism'. He describes the deformity of the toes as a 'griffe' (or claw), on account of the extension of the first and concomitant flexion of the second phalanges. Hughlings Jackson (1899) also mentions deformity of hands seen in some cases of Parkinsonism. He remarked that 'in paralysis agitans the interossei are the muscles of the hand which are preponderatingly affected and the set of the hand resembles that of tetany of children'. Cooper and Bravo (1958) show that the deformity of the hands in a case of Parkinsonism was relieved by unilateral occlusion of the anterior choroidal artery. The deformities of the hands and feet add to the difficulties of severely handicapped patients. In suitable cases most of these deformities are reversible by operation on the thalamus. The typical deformities will be described, their mode of production discussed, and it will be shown that they are reversible by stereotactic lesions of the thalamus.