What Are the Corpora Cavernosa?

The corpus cavernosum, also known as the cavernous body or cavernous muscle, is the hardest smooth muscle and connective tissue structure 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 joins the expanded portion of the corpus spongiosum (urethral sponge); posteriorly, each bifurcates into a crus (crural extension) that attaches to the ipsilateral pubic ramus. Due to its sponge-like internal architecture, this tissue becomes engorged with blood during erection, resulting in penile rigidity and enlargement; conversely, it shrinks when flaccid. Asymmetrical development of the two corpora cavernosa may cause curvature of the erect penis toward the underdeveloped side; however, injuries to this tissue generally heal readily with good functional restoration.

The corpus cavernosum receives dual blood supply systems, each serving distinct physiological functions. During the flaccid state, blood flow primarily traverses the capillary network to provide nutritive support.

Spiral arteries regulate blood flow into the corpus cavernosum. Beneath their endothelium lies a subendothelial cushion composed of smooth muscle. When this cushion relaxes, the spiral 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 engorged cavernous sinuses, playing a critical role in the veno-occlusive mechanism essential for sustaining erection.