A three-dimensional theoretical model of the relationship between cavernosal expandability and percent cavernosal smooth muscle.

Introduction: Percent corporal smooth muscle content, a traditional predictor of corporal veno-occlusive function, is invasive and clinically assessed by histomorphometric analyses of erectile tissue biopsies. Cavernosal "expandability" which may be a more physiologically relevant parameter is a measure of work performed to achieve penile erection, and as a consequence, an indicator of the ability to approach maximum penile volume at low intracavernosal pressure.

Aim: To demonstrate that cavernosal "expandability" determined by noninvasive methodology can replace the determination of percent smooth muscle.

Biomechanics of male erectile function.

Two major branches of engineering mechanics are fluid mechanics and structural mechanics, with many practical problems involving the effect of the first on the second. An example is the design of an aircraft's wings to bend within reasonable limits without breaking under the action of lift forces exerted by the air flowing over them; another is the maintenance of the structural integrity of a dam designed to hold back a water reservoir which would exert very large forces on it. Similarly, fluid and structural mechanics are involved in the engineering analysis of erectile function: it is the hydraulic action of increased blood flow into the corpora cavernosa that creates the structural rigidity necessary to prevent collapse of the penile column.