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September 1935


Arch NeurPsych. 1935;34(3):520-532. doi:10.1001/archneurpsyc.1935.02250210041003

Walshe1 has gone far to explain the mechanism of rigidity appearing in man after injury of the pyramidal tracts, in terms of recent neurophysiologic data. He expressed the belief that the hypertonus is equivalent to that following partial decerebration in laboratory animals and is due to freeing of reflexes of the midbrain from normal control by higher centers. The rigidity that develops after recovery from a cerebrovascular accident involving the corticospinal fibers in the internal capsule is commonly distributed in a stereotyped pattern. The increased tone in the arm is maximal in the flexors of the wrist and fingers, the flexors and pronators of the forearm and the adductors of the upper arm; the attitude of the arm is primarily one of flexion. In the leg the hypertonus is predominate in the flexors of the foot and toes, in the extensors of the knee and in the adductors of