[Anatomic prerequisites of the physiologic process of erection]

The performance of numerous anatomical and physiological investigations of tissue has allowed a new concept of the penile architecture with implications for the erectile mechanism. As demonstrated the tissue in the cavernous body of the penis is subject to both parasympathetic and sympathetic influences. Penile erection is the result of three interacting mechanisms: (1) arterial dilatation with an increase in penile blood flow; (2) relaxation of the corporeal smooth muscle and consequent decrease in resistance along with intracorporeal volume and pressure increase; and (3) venous restriction following compression of the venous drainage system inside the tunica of the corporeal bodies.