Penis

The penis (plural penises or penes) or phallus is the male copulatory organ, and, in mammals, the male organ of urinary excretion. It is homologous to the female clitoris, as it develops from the same embryonic structure. The male sexual organs comprise both the penis and the testes.

The kangaroo and other marsupials have a bifurcated penis. That is, it separates into two separate columns, and so the penis terminates in two ends. The dolphins have independent control over their penises, so they use it as an appendage[?] to feel the bottom with. The barnacle has the longest penis for its own length: up to twenty times the length of the animal.

The remainder of this article specifically discusses the human penis. It differs from other mammalian penises by lacking an erectile bone[?], instead relying entirely on engorgement with blood to reach its erect state, lacking the ability to be withdrawn into the groin, and being larger than average in proportion to body mass.

Table of contents 1 Structure 2 Erection 3 Size 4 Disorders affecting the penis 5 Body Modification

Structure

The human penis is built of three columns of erectile tissue:

• the two corpora cavernosa[?] and
• one corpus spongiosum[?] which lies below them.

The end of corpus spongiosum is enlarged and cone-shaped and forms the very sensitive glans penis. The glans is protected by the foreskin or prepuce, a loose fold of skin that can retract to expose the glans. For various culturual, religious and medical reasons, the foreskin is sometimes partly or completely removed; this is called circumcision. The area on the underside of the penis, where the foreskin attaches, is called the frenum (or frenulum).

The urethra, which is the last part of the urinary tract[?], traverses the corpus spongiosum and its end lies on the tip of the glans penis. It is both a passage for urine and for semen ejaculation. Sperm is produced in the testes and stored in the attached epididymis[?]. During ejaculation, sperm are propelled up the vas deferens[?], two ducts that pass over and behind the bladder. Fluids are added by the seminal vesicles[?] and the vas deferens turns into the ejaculatory ducts[?] which join the urethra inside the prostate gland. The prostate as well as the bulbourethral glands[?] add further secretions, and the semen is expelled through the penis.

Erection

Erection is a stiffening and hardening of the penis which occurs in the sexually aroused male. Erection enables sexual intercourse, though it is not essential, and some other sexual activities.

Size

In comparison to body size, the human male penis is among the largest of the primates. From polling, the average human male penis is 5 1/2 inches (14 cm) in length when fully engorged with blood during arousal, though this varies quite a bit. The size of a flaccid human penis has an even greater variation in both length and width that often does not predict the size of a fully aroused member. For example, a man with a relatively small flaccid penis may have an above average length penis when fully aroused. The opposite is also true.

Disorders affecting the penis

In Peyronie disease, anomalous scar tissue grows in the soft tissue of the penis.

Pudendal Nerve Entrapment[?] is a condition characterized by pain on sitting and loss of penis (or clitoris) sensation and orgasm. In fact, sometimes there is a total loss of sensation and orgasm. The pudendal nerve can be damaged by narrow hard cycle seats and accidents. In females it commonly occurs as a result of childbirth. It is treated in France (the leaders in this area), America and Egypt.

Body Modification

The penis is sometimes pierced and modified by other body art. Piercings of the penis include the Prince Albert piercing, the Apadrayva piercing, the Ampallang piercing, the dido piercing[?], the frenum piercing[?] and others.

Other physical modifications to the penis are also performed by some people, although they are considered very extreme. Apart from a penectomy, perhaps the most radical of these is the subincision, in which the glans penis is bifurcated to look similar to that of the kangaroo. This modification was originally done among Australian Aborigines, although it is now done by some in the U.S. and Europe.

A small number of men who are circumcised attempt to restore their foreskin through various means, including surgical. This is called foreskin restoration.

Some men seek penis enlargement.

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See also: impotence, penis envy, priapism, circumcision, sexual intercourse, Sexual slang, and the movie Percy.