Hemodynamic mechanism of erection in the human penis.

Six infertile patients and one patient with ureteral calculus were studied to elucidate the intrapenial hemodynamics of erection. Xe-133 was infused into the corpus cavernosum and visual sexual stimulation (V.S.S.) provided to induce erection. Xe-133 clearance curves declined at a uniform rate in the nonerect penis without V.S.S. Xe-133 clearance curves for five patients with complete erection at V.S.S. indicated a sudden drop upon erection. Unlike previous reports, it was noted that penial erection can occur independently of a venous-return blocking mechanism.