The Physiology of Human Penile Erection

Human penile erection depends on integration of afferent signals in the thoracolumbar or sacral erection centers, intact autonomic nerves to the penis, normal erectile tissues, and an adequate blood supply to the penis. Cerebral influence is apparently not always necessary to facilitate erection and may even inhibit penile erection. Considering the tremendous importance of penile erection to nearly all of our patients, it is surprising to find how incomplete our knowledge is on many aspects of this fascinating neurophysiologic and hemodynamic process.