Scrotum
| 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. | |
| Details | |
| Precursor | labioscrotal folds |
| Identifiers | |
| MeSH | D012611 |
| TA98 | A09.4.03.001 A09.4.03.004 |
| TA2 | 3693 |
| FMA | 18252 |
| Anatomical terminology | |
In some male mammals, the scrotum is an external bag of skin and muscle containing the testicles. It is an extension of the abdomen, and is located between the penis and anus. The female homologue during fetal development is the labia majora.
In humans and some other mammals the base of the scrotum becomes covered with pubic hair at puberty.
The area below the scrotum is the perineum.
Function
The function of the scrotum appears to be to keep the testicles 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) appears to be ideal; 36.7 degrees Celsius (98 degree Fahrenheit) may be damaging to sperm count. The temperature is controlled by making the scrotum tighter or looser, hence moving the testicles closer to the abdomen when it is cold, and away when hot, through the cremasteric reflex, the gradual tightening and loosening of the cremaster muscle in the abdomen and the dartos fascia (muscular tissue under the skin) in the scrotum.
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 them vulnerable in many species, there is some debate on the evolutionary advantage of such a system. One theory is that making sperm highly sensitive to elevated body temperature prevents impregnation of females who are ill.
Health issues
A common problem of the scrotum is the development of masses. Common scrotal masses include
- sebaceous cyst, also called a 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
See also
- Raphe
- Sex organ
- Castration
- Blue balls
- Teabagging
- Telmatobius culeus, a frog whose name means "Aquatic scrotum"