Penile shaft

Corpus cavernosum penis
Transverse section of the penis.
The constituent cavernous cylinders of the penis.
Details
Identifiers
Latin	corpus cavernosum penis
Dorlands /Elsevier	12260417
TA	A09.4.01.014
FMA	19618
Anatomical terminology []

A corpus cavernosum penis (singular) (cavernous body of the penis) is one of a pair of sponge-like regions of erectile tissue, the corpora cavernosa (plural) (cavernous bodies), which contain most of the blood in the penis during an erection. Such a is homologous to the corpus cavernosum clitoridis in the female; the body of the clitoris contains erectile tissue in a pair of corpora cavernosa (literally "cave-like bodies") with a recognisably similar structure.

The two corpora cavernosa and corpus spongiosum (also known as the corpus cavernosum urethrae in older texts and in the adjacent diagram) are three expandable erectile tissues along the length of the penis, which fill with blood during penile erection. The two corpora cavernosa lie along the penis shaft, from the pubic bones to the head of the penis, where they join. These formations are made of a sponge-like tissue containing trabeculae, irregular blood-filled spaces lined by endothelium and separated by connective tissue septa.

The male anatomy has no vestibular bulbs, but instead a corpus spongiosum, a smaller region along the bottom of the penis, which contains the urethra and forms the glans penis.

In some circumstances, release of nitric oxide precedes relaxation of muscles in the corpora cavernosa and corpus spongiosum, in a process similar to female arousal. The spongy tissue fills with blood, from arteries down the length of the penis. A little blood enters the corpus spongiosum; the remainder engorges the corpora cavernosa, which expand to hold 90% of the blood involved in an erection, increasing both in length and in diameter. The function of the corpus spongiosum is to prevent compression of the urethra during erection.