Scrotum

From Wikipedia, the free encyclopedia

Scrotum

The scrotum. On the left side the cavity of the tunica vaginalis has been opened; on the right side only the layers superficial to the Cremaster have been removed.
Gray's	subject #258 1237
Artery	Anterior scrotal artery & Posterior scrotal artery
Vein	Testicular vein
Nerve	Posterior scrotal nerves, genital branch of genitofemoral nerve, perineal branches of posterior femoral cutaneous nerve
Lymph	Superficial inguinal lymph nodes
Precursor	labioscrotal folds
MeSH	Scrotum
Dorlands/Elsevier	s_06/12726162

In some male mammals, the scrotum is a protuberance of skin and muscle containing the testicles. It is an extension of the abdomen, and is located between the penis and anus.

In humans, and some other mammals, the base of the scrotum becomes covered with pubic hair at puberty.

The area behind the scrotum is the perineum.

1 Function
2 Health issues
3 Additional images
4 Children's book controversy
5 See also

The function of the scrotum appears to be to keep the testes at a temperature slightly lower than that of the rest of the body. For the human, a temperature around 34.4 degrees Celsius (94 degrees Fahrenheit) seems to be ideal; 36.7 degrees Celsius (98 degree Fahrenheit) may be damaging to sperm count. The temperature is controlled by moving the testicles closer to the abdomen when it is cold, and away when hot. This is done by the contracting and relaxing of the cremaster muscle in the abdomen and the dartos fascia (muscular tissue under the skin) in the scrotum.

In most men, the cremaster muscle itself cannot be controlled voluntarily. Contraction of the abdominal muscles, and changes in intraabdominal pressure, often can lift and lower the testicles within the scrotum. Contraction of the muscle fibers of the dartos tunic (or fascia) is completely involuntary and results in the appearance of increased wrinkling and thickening of the scrotal skin. The testicles are not directly attached to the skin of the scrotum, so this dartos contraction results in their sliding toward the abdomen.

Although the ideal temperature for sperm growth varies between species, it usually appears, in warm-blooded species, to be a bit cooler than internal body temperature, necessitating the scrotum. Since this leaves the testicles vulnerable in many species, there is some debate on the evolutionary advantage of such a system. One theory is that the impregnation of females who are ill is less likely when sperm is highly sensitive to elevated body temperatures.

An alternative explanation is to protect the testes from jolts and compressions associated with an active lifestyle. Animals that have 'stately' movements - such as elephants, whales and marsupial moles - have internal testes and no scrotum.[1]'s

A common problem of the scrotum is the development of masses. Common scrotal masses include

Sebaceous cyst, also called an epidermal cyst
hydrocele
hematocele
spermatocele
varicocele

Other conditions include:

contact dermatitis: may cause redness, swelling, and itching of the entire scrotum. Can result from soaps, solvents, detergents, and natural irritants such as poison ivy.
inguinal hernia
yeast infection
swelling resulting from conditions external to the scrotum, including:
- heart failure
- kidney or liver disease

Structure of the male genitalia.

Vertical section of bladder, penis, and urethra.

The superficial branches of the internal pudendal artery.

This article documents a current event.
Information may change rapidly as the event progresses.

The children's book, The Higher Power of Lucky written by librarian Susan Patron, has been removed by a few school librarians because of the use of the word in the second paragraph of the book. As reported in the Books section of the New York Times in the Sunday February 18, 2007 issue, the book set off a firestorm amongst librarians.