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Penis is a copulation organ formed by erectile bodies, their envelopes and part of the urethra. The basic anatomical and functional part of the penis consists in two geminate, side-by-side situated cavernous (erectile) bodies and one non-geminate, spongy body, which surrounds the urethra and at its end turns into a conical-shaped glans.

The radix (radix penis) is formed by geminate arms (crura penis), which are fixed to the margin of pubic bones, and bulbus penis, which adjoins the diaphragma urogenitale. From above, it receives the urethra. The surface of bulbus penis is covered by m. bulbospongiosus, which passes to the posterior part of the cavernous body and to a part of the spongy body. Similarly, the surface of crura penis is covered by m. ischiocavernosus. The penis is connected with pubic physis and linea alba by two fibrous bands (ligamentum suspensorium and fundiforme).

Cavernous bodies are covered with a thick layer of connective tissue (tunica albuginea), which forms an incomplete septum between both cavernous bodies (septum penis). From tunica albuginea downwards derive fibrous trabeculae admixed with smooth musculature. The trabeculae divide venous spaces lined with endothelim (cavernae) and are crossed by helicine arteries (aa. helicinae), which open into the cavernous spaces. In the aa. helicinae wall, under the endothelium, there are cushions of smooth musculature regulating the blood flow. The blood is drained from the cavernae by vv. cavernosae, which end in the veins of the penis.

The spongy body contains a weakly formed fibrous skeleton. Tunica albuginea and trabeculae are thin and also contain smooth muscle cells. Tunica albuginea is not formed on the glans penis and endothelial spaces correspond by their structure to venous plexus.

The glans (glans penis) is the ending part of the spongy body. It is divided from the penis body by a groove (collum glandis), which receives sebaceous glands producing smegma. The surface of the glans is covered with retractile prepuce (praeputium), which is connected with the lower part of the glans by a frenum (frenulum praeputii). At the glans apex the urethra ends in a vertical fissure (ostium urethrae externum).

The skin of the penis is thin, tensile and freely pigmented. On the lower side of the penis, a longitudinal raphe is formed (raphe penis), which is a remnant of adhesion of the genital ridges in the early developmental stages. The fibrous envelope of the penis forms fascia superficialis penis in the subcutis, and fascia profunda penis on the surface of erectile bodies.

The male penis fulfills three functions:

• it voids urine from the urinary bladder by the urethra
• it is the organ for sexual intercourse
• it drains the semen (ejaculate) during semen emission (ejaculation) by the urethra