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 dense, 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 (crural extension) that attaches to the ipsilateral pubic ramus. Due to its sponge-like internal architecture, this tissue engorges with blood during erection, causing penile enlargement; conversely, it shrinks when flaccid. Asymmetrical development of the two corpora cavernosa may result in penile curvature toward the underdeveloped side during erection; however, injuries to this tissue generally heal well with effective reconnection.

The corpus cavernosum receives blood supply via two distinct vascular systems, each serving unique physiological functions. During the flaccid state, blood primarily perfuses the capillary network to provide nutritional support.

The helicine arteries regulate blood flow into the erectile tissue. Beneath their endothelium lies a subendothelial cushion composed of smooth muscle. When this cushion relaxes, the helicine arteries dilate and open, allowing blood to flood the cavernous sinuses and induce penile erection. During erection, the subtunical venous plexus becomes compressed between the tunica albuginea and the cavernous sinuses, playing a critical role in the veno-occlusive mechanism essential for sustaining erection.