What Are the Corpora Cavernosa?

The corpus cavernosum, also known as the cavernous muscle, is the hardest smooth muscle and connective tissue in the human body. It is an erectile tissue enveloped by a thick, fibrous tunica albuginea. Internally, it consists of a sponge-like framework composed of connective tissue and smooth muscle, with its lacunar spaces communicating directly with blood vessels.

There are two corpora cavernosa in the penis, located dorsally and shaped like tapered cones. They lie side-by-side in close apposition. Anteriorly, each corpus cavernosum connects to the expanded portion of the corpus spongiosum; posteriorly, each bifurcates into a crus (plural: crura) of the corpus cavernosum, which attaches separately to the ipsilateral pubic rami. Due to its sponge-like internal architecture, this tissue engorges with blood during erection, resulting in penile rigidity and enlargement; conversely, it shrinks during the flaccid state. Asymmetrical development of the two corpora cavernosa may cause penile curvature toward the underdeveloped side during erection; however, injuries to this tissue generally heal readily with good functional restoration.

The corpus cavernosum receives blood supply via two distinct vascular systems, each serving specific physiological functions. During the flaccid state, blood flow occurs predominantly through the capillary system to provide nutritional support.

The helicine arteries regulate blood flow into the corpus cavernosum. Their subendothelial layer contains smooth muscle–rich subendothelial pads; when these pads relax, the helicine arteries dilate and open, allowing blood to flood the cavernous sinuses and thereby induce penile erection. During erection, the subtunical venous plexus becomes compressed between the tunica albuginea and the engorged cavernous sinuses, playing a critical role in the veno-occlusive mechanism essential for maintaining erection.