Penis

Penis, male reproductive organ for introducing sperm and semen into the female vagina and uterus; its urethra also carries urine from the bladder. The penis is made of connective tissues and specialized blood vessels which become engorged with blood in sexual arousal and which cause the penis to become stiff and erect; this facilitates the intromission of semen in sexual intercourse. A protective fold, the foreskin, covers the top and is often removed for religious or medical reasons in circumcision.

The penis has a fixed root situated in the urogenital triangle of the perineum and a free shaft. At the root of the corpora cavernosa diverge to be attached to the boney structure of the pelvis. The corpus spongiosum expands to form the bulb of the penis.

The skin of the shaft of the penis forms a fold, the prepuce, which projects from a sulcus to cover the glans. The skin of the penis is thin, distensible, devoid of fat, and closely attached to the underlying fascia. On one end it is continuous with the skin of the abdominal wall, and the scrotum and peritoneum.

See also: Reproduction.