Abstract
Disturbance of autonomic function is an unusual feature of compression of the cauda equina. A 61 year old man who had complete occlusion of the lumbar spinal canal with compression of the cauda equina from a large centrally prolapsed disc, had spontaneous priapism, precipitated by walking and relieved by resting. This symptom was comparable to claudication by compression of cauda equina. It subsided completely after surgical removal of a prolapsed L4-5 disc.