In simple terms, producing erections consists of trapping pressurized blood within the confines of a limited space. The chambers that accomplish this anatomically are known as the corpora cavernosa. Given the proper signal the spongy, blood filled spaces relax and open up, allowing the free inflow of blood.
The chambers expand, pulling the tight. Its tension makes the corpora hard (resistant to indentation) and rigid (resistant to flexion). Secondarily, it pinches off the veins that normally let blood exit the chambers, trapping blood inside and contributing to the state of engorgement.
Can bent or curved erections cause impotence?
Impotence, defined as the inability to maintain a hard enough erection to have intercourse, is uncommon in Peyronie’s disease. Yet it frequently affects the erection mechanism in a less serious way. Scientific studies have shown that at some point in time, up to 40% of men with Peyronie’s disease have experienced some degree of erectile dysfunction. Usually, this consists of a reduction in maximum hardness. It is usually a temporary effect, and rarely causes enough softening to preclude normal intercourse. When associated with severe bent erections however, it can be a problem. Persistent difficulty with erectile rigidity can usually be treated medically.
The cause for the erectile dysfunction of Peyronie’s disease is “venous leakage.” In other words, the blood that should normally be trapped within the taut confines of the tunica albuginea is leaking slowly out. By locally hardening the tunica, plaques may prevent the exit veins from pinching off in the normal fashion.
Damaging effects of mechanical stress on erections
When fully expanded, the rigid corpora cavernosa forms something like an inflatable I beam. Mechanical forces on this structure will create a unique region of tissue stress at the top of the “I”. The majority of the tunica albuginea compresses with stretch during erection, but the topmost strip is subject to an opposite, delaminating force.
Fibrin deposition, the first step in the wound healing process and the precursor to Peyronie’s plaque, usually develops in this area. The mid- top of the penis is the area most commonly involved by Peyronie’s disease.
If Peyronie’s plaque forms in the hoop (circumfrential) direction, it causes indentation or segmental loss of penile diameter and curved erections. These so-called hourglass areas have a profound effect on over all penile rigidity. The resistance to bending of an inflatable tube is related to its cross sectional area. Because of this, indented areas make bent erections more likely, even at high internal fluid pressures.
By looking at the expanding corpora as a series of stacked elements, it is possible to calculate how much tunica must lose its elasticity to produce a given amount of bending. A plaque about six centimeters long is required in order to produce a 90 degree bend. In other words, little plaques cannot cause big bends.