In most terrestrial , the scrotum (: scrotums or scrota; possibly from Latin scortum, meaning "hide" or "skin")
The scrotum is homologous to the labia majora in females.
Structure
In regards to humans, the scrotum is a suspended two-chambered sac of
Human skin and
muscular tissue containing the testicles and the lower part of the
. It is located behind the
Human penis and above the
perineum. The
perineal raphe is a small, vertical ridge of skin that expands from the
Human anus and runs through the middle of the scrotum front to back. The scrotum is also a distention of the perineum and carries some abdominal tissues into its cavity including the testicular artery,
testicular vein, and pampiniform plexus.
Nerve supply
|
|
| anterolateral |
| anterior |
| posterior |
| inferior |
Blood supply
|
|
originates from the deep external pudendal artery |
| |
| |
|
Skin and glands
The skin on the scrotum is more highly pigmented in comparison to the rest of the body. The Scrotal septum is a connective tissue membrane dividing the scrotum into two cavities.[
]
Lymphatic system
The scrotal lymph initially drains into the superficial inguinal lymph nodes, this then drains into the deep inguinal lymph nodes. The deep inguinal lymph nodes channel into the common iliac, which ultimately releases lymph into the cisterna chyli.
Asymmetry
One testis is typically lower than the other, which is believed to function to avoid compression in the event of impact; in humans, the left testis is typically lower than the right.
An alternative view is that testis descent asymmetry evolved to enable more effective cooling of the testicles.
Internal structure
Additional tissues and organs reside inside the scrotum and are described in more detail in the following articles:
Development
During the fifth week after fertilization, the
genital ridge grows behind the peritoneal membrane. By the sixth week, string-like tissues called primary sex cords form within the enlarging genital ridge. Externally, a swelling called the genital tubercule appears over the cloacal membrane.
Testosterone secretion starts during week eight, reaches peak levels during week 13 and eventually declines to very low levels by the end of the second trimester. The testosterone causes the masculinization of the labioscrotal folds into the scrotum. The Penile raphe is formed when the embryonic, urethral groove closes by week 12.
Scrotal growth and puberty
Though the testes and scrotum form early in embryonic life, sexual maturation begins upon entering
puberty. The increased secretion of testosterone causes the darkening of the skin and development of
pubic hair on the scrotum.
Function
The scrotum regulates the temperature of the testicles and maintains it at , i.e. two or three degrees below the body temperature of . Higher temperatures affect
spermatogenesis. Temperature control is accomplished by the
of the scrotum moving the testicles either closer to or further away from the abdomen dependent upon the ambient temperature. This is accomplished by the
cremaster muscle in the abdomen and the
dartos fascia (muscular tissue under the skin that makes the scrotum appear wrinkly).
During sexual arousal, the scrotum will also tighten and thicken in the course of Erection.
Having the scrotum and testicles situated outside the abdominal cavity may provide additional advantages. The external scrotum is not affected by abdominal pressure. This may prevent the emptying of the testes before the sperm were matured sufficiently for fertilization. Another advantage is it protects the testes from jolts and compressions associated with an active lifestyle. The scrotum may provide some friction during intercourse, helping to enhance the activity.
Society and culture
Common slang terms for the scrotum are
ballsack,
nutsack, and
teabag.
Some men will get a Genital piercing on the skin of the scrotum, any of which is called a hafada (e.g., scrotal ladder). Side-to-side or front-to-back piercings that pass through the scrotum are known as transscrotal piercings.
Scrotoplasty is a sex reassignment surgery that creates a scrotum for trans men using tissue from the labia majora, or a plastic surgery that repairs or reconstructs the scrotum.
Cock and ball torture is a kink that may involve bringing pain to the scrotum. Beyond kink, a person (especially a man) may hit someone in the testicles as a gendered cultural practice known as sack tapping. This phenomenon is complex and contains many (often conflicting) meanings: it is used to both strengthen inclusive bonds and reinforce exclusive hierarchies, it is both humorous and violent, and both juvenile and present in male-dominated social spheres beyond those of adolescence.
Other animals
A scrotum is present in all
land mammals except
,
,
, moles,
,
, and numerous families of
and
.
The
anus is separated from the scrotum by the
perineum in these mammals. The testicles remain in the body cavity in all other vertebrates, including
animals.
Unlike Placentalia, some male marsupials have a scrotum that is anterior to the penis,
The scrotum is also absent in , such as , , and Pinniped,
Clinical significance
Diseases and conditions
The scrotum and its contents can develop many diseases and can incur injuries. These include:
-
Varicocele - enlargement of the pampiniform venous complex
-
Inguinal hernia
-
Epididymo-orchitis
-
Testicular torsion
-
Pruritus scroti - irritation of the scrotum (itchiness)
-
Genital warts - sexually transmitted infection
-
Testicular cancer
-
Dermatitis
-
Undescended testes (also known as cryptorchidism)
-
Chyloderma - swollen scrotum caused by a lymphatic obstruction
-
Mumps
-
Scabies
-
Herpes - sexually transmitted infection
-
Pubic lice
-
Chancroid ( Haemophilus ducreyi) - sexually transmitted infection
-
Chlamydia ( Chlamydia trachomatis) - sexually transmitted infection
-
Gonorrhea ( Neisseria gonorrhoeae) - sexually transmitted infection
-
Granuloma inguinale or ( Klebsiella granulomatis)
-
Syphilis ( Treponema pallidum) - sexually transmitted infection
-
Scrotal eczema
-
Polyorchidism - the presence of three or more testicles
-
Scrotal psoriasis disease
-
Riboflavin deficiency
-
Chimney sweeps' carcinoma (scrotal cancer)
See also
-
Retroperitoneal lymph node dissection
-
Scrotal infusion, a temporary form of body modification
-
Testicular self-examination
Bibliography
- Books
External links
