We have studied the histopathology of 87 dorsal penile veins, obtained from patients who underwent a resection of the deep dorsal penile vein because of proven venous leakage. The amount of muscle tissue and of collagenous connective tissue has been numerically quantified. Special attention has been focused on the muscular/collagenization ratio. We show that this ratio is not correlated to age neither with the outcome of the operation and that no differences exist between veins in venous leakage patients and in potent patients. This study confirms that the reduction of venous outflow-the so called corporeal veno-occlusive mechanism-is probably a secondary passive phenomenon, due to smooth muscular relaxation, and mainly located within the corpora cavernosa, between the expanding sinusoidal wall and the noncompliant tunica albuginea. Our findings also strongly refute the hypothesis that polsters or other venous wall characteristics contribute to the normal physiology of the deep dorsal penile vein.