(解剖)陰嚢

関: scrotal

WordNet

the external pouch that contains the testes
relating to or having or lying within a scrotum; "scrotal mammals"; "scrotal testes"

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陰嚢(いんのう)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/02/22 14:30:04」(JST)

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For the obsolete dinosaur fossil name, see Megalosaurus#"Scrotum humanum".

The scrotum is a dual-chambered protuberance of skin and muscle, present in some male mammals, that contains the testicles and is divided by a septum.^[1] It is an extension of the perineum, and is located between the penis and anus. In humans and some other mammals, the scrotum becomes covered with pubic hair at puberty.

The scrotum is biologically homologous to the labia majora in females.

Structure

Innervation

Nerve	Surface^[2]
Genital branch of genitofemoral nerve	anterolateral
Anterior scrotal nerves (from ilioinguinal nerve)	anterior
Posterior scrotal nerves (from perineal nerve)	posterior
perineal branches of posterior femoral cutaneous nerve	inferior

Function

Image showing musculature and inner workings of the scrotum.

The function of the scrotum is to keep the temperature of the testes at about 35-36 degrees Celsius (95-96.8 degrees Fahrenheit), i.e. one to two degrees below the body temperature of 37 degrees Celsius (98.6 degrees Fahrenheit).^[3] High scrotum temperature is damaging to sperm production.^{[citation needed]} Temperature control is accomplished by the smooth muscles 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).^{[citation needed]}

A circumcised human penis in the cold: the shaft has shrunk, excess shaft skin has covered the glans, and the scrotum has also shrunk to pull the testes closer to the body to keep them at the optimum temperature.

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.^[4] Some mammals — elephants and marine mammals, for example – do keep their testes within the abdomen and there may be mechanisms to prevent this inadvertent emptying.

Diagram of 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 muscle have been removed.

Abdominal muscles, and changes in intra-abdominal pressure, can often 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. They also, in some men, can be lifted the same way by tightening the anus and pelvic muscles, doing Kegel exercises.

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, making the scrotum necessary. 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.^[5]

Clinical significance

A study has indicated that use of a laptop computer positioned on the lap can negatively affect sperm production.^[6]^[7]

A common problem of the scrotum is the development of masses. Common scrotal masses may have any of a variety of causes, including a sebaceous cyst, also called an epidermal cyst; a hydrocele, a hematocele, a spermatocele or a varicocele.

Another condition is blisters caused by chafing or scratching of the scrotum while it is damp. This condition is often seen in males undergoing puberty, as emerging pubic hairs cause an itch and an urge to scratch. Powdering the scrotum to absorb moisture can help to prevent this discomfort. Contact dermatitis may cause redness, burning, swelling, and itching of the entire scrotum. It can result from soaps, solvents, detergents, and natural irritants such as poison ivy. Inguinal hernia and yeast infection may occur, and there may be swelling resulting from conditions external to the scrotum, including heart failure, kidney or liver disease, cherry angioma and testicular torsion.

Skin conditions which have not been successfully identified may be referred to as non-specific scrotal dermatitis.

References

^ "Scrotum". National Institutes of Health. Retrieved 6 January 2011.
^ Moore, Keith; Anne Agur (2007). Essential Clinical Anatomy, Third Edition. Lippincott Williams & Wilkins. p. 132. ISBN 0-7817-6274-X.
^ "About the Male Reproductive System". KidsHealth. Retrieved 6 January 2011.
^ "Science : Bumpy lifestyle led to external testes - 17 August 1996 - New Scientist". Retrieved 2007-11-06.
^ "Science : Bumpy lifestyle led to external testes - 17 August 1996 - New Scientist". Retrieved 2007-11-06.
^ "Laptops may damage male fertility". BBC News. 2004-12-09. Retrieved 2012-01-30.
^ Sheynkin, Yefim; et al. (February 2005). "Increase in scrotal temperature in laptop computer users". Hum. Reprod. 20 (2): 452–455. doi:10.1093/humrep/deh616. PMID 15591087.

Additional images

Vertical section of bladder, penis, and urethra.
The superficial branches of the internal pudendal artery.

UpToDate Contents

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1. 成人における急性陰嚢症の評価 evaluation of the acute scrotum in adults
2. 成人男性における非急性陰嚢疾患の評価 evaluation of nonacute scrotal pathology in adult men
3. 小児および思春期における陰嚢損傷 scrotal trauma in children and adolescents
4. 小児および思春期における陰嚢痛または腫脹の評価 evaluation of scrotal pain or swelling in children and adolescents
5. HIV感染患者における性器単純ヘルペスウイルスの疫学、臨床症状、および診断 epidemiology clinical manifestations and diagnosis of genital herpes simplex virus in hiv infected patients

English Journal

Race and prevalence of human papillomavirus infection among men residing in Brazil, Mexico and the United States.

Akogbe GO, Ajidahun A, Sirak B, Anic GM, Papenfuss MR, Fulp WJ, Lin HY, Abrahamsen M, Villa LL, Lazcano-Ponce E, Quiterio M, Smith D, Schabath MB, Salmeron J, Giuliano AR.SourceDepartment of Cancer Epidemiology, H Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA.
International journal of cancer. Journal international du cancer.Int J Cancer.2012 Aug 1;131(3):E282-91. doi: 10.1002/ijc.27397. Epub 2012 Jan 11.
Human papillomavirus (HPV) causes anal, penile and oropharyngeal cancers in men. Genital HPV prevalence in men appears to vary by world region with men residing in Asia having among the lowest prevalence. Unfortunately, there is little information on prevalence of HPV infection in men by race. The p
PMID 22161806

Unusual systemic metastases of malignant seminoma in a dog.

Lucas X, Rodenas C, Cuello C, Gil M, Parrilla I, Soler M, Belda E, Agut A.SourceAnimal Surgery and Medicine Department, Veterinary Hospital Teaching, University of Murcia, Espinardo, Murcia, Spain.
Reproduction in domestic animals = Zuchthygiene.Reprod Domest Anim.2012 Aug;47(4):e59-61. doi: 10.1111/j.1439-0531.2011.01927.x. Epub 2011 Nov 2.
Unilateral enlargement of left testicle and scrotum was detected in an 8-year-old West Highland White Terrier. The histopathological diagnosis after surgery was a seminoma (SEM) tumour, and a diagnosis of metastatic foci was also detected in vaginal tunic and scrotum. Two months later, new metastati
PMID 22044725

Japanese Journal

陰内に及ぶ巨大後腹膜脂肪肉腫の1例

正岡寛之,柴田舞子,高野徳昭
西日本泌尿器科 = The Nishinihon journal of urology 74(10), 580-584, 2012-10
NAID 40019470704

右陰内に発生したangiomyofibroblastoma-like tumorの1例

三井要造,安食春輝,小原千明 [他]
西日本泌尿器科 = The Nishinihon journal of urology 74(9), 516-520, 2012-09
NAID 40019417602

Related Pictures

★リンクテーブル★

リンク元	「陰嚢」「scrotal」

「陰嚢」

Scrotum
	Human scrotum (both distended and undistended states)
Details
Latin	Scrotum
Precursor	labioscrotal folds
Artery	Anterior scrotal artery & Posterior scrotal artery
Vein	Testicular vein
Nerve	Posterior scrotal nerves, Anterior scrotal nerves, genital branch of genitofemoral nerve, perineal branches of posterior femoral cutaneous nerve
Lymph	Superficial inguinal lymph nodes
Identifiers
Gray's	p.1237
MeSH	A05.360.444.661
Dorlands; /Elsevier	12726162
TA	A09.4.03.001
FMA	18252
	Anatomical terminology

　　[★]

英: scrotum (M,Z)
関: 外性器

平滑筋と皮膚からなる袋で2層からなる (M.127)
女性の外生殖器では大陰唇に相当 (KH.254,KL.482)

色素の豊富な皮膚
肉様膜

肉様膜筋は皮膚に付着し、収縮することにより陰嚢にシワを寄せている

解剖

肉様膜：カンパー筋膜(腹部の皮下組織)から連続
外精筋膜：外腹斜筋膜と連続
精巣挙筋：内腹斜筋と連続
内精筋膜：腹横筋膜と連続
精巣鞘膜：腹膜の遺残

血管 (M.127)

動脈

前陰嚢動脈

大腿動脈-外陰部動脈

後陰嚢動脈

内陰部動脈-会陰動脈

静脈

動脈に伴行

神経 (M.127)

臨床関連

陰嚢の腫脹：鑑別として精巣腫瘍、陰嚢水腫、精巣上体炎、精巣炎、鼡径ヘルニアがあげられる。
陰嚢の疼痛：

「scrotal」

　　[★]

陰嚢の

関: scrotum

[1] "Scrotum". National Institutes of Health. Retrieved 6 January 2011.

[2] Moore, Keith; Anne Agur (2007). Essential Clinical Anatomy, Third Edition. Lippincott Williams & Wilkins. p. 132. ISBN 0-7817-6274-X.

[3] "About the Male Reproductive System". KidsHealth. Retrieved 6 January 2011.

[4] "Science : Bumpy lifestyle led to external testes - 17 August 1996 - New Scientist". Retrieved 2007-11-06.

[5] "Science : Bumpy lifestyle led to external testes - 17 August 1996 - New Scientist". Retrieved 2007-11-06.

[6] "Laptops may damage male fertility". BBC News. 2004-12-09. Retrieved 2012-01-30.

[7] Sheynkin, Yefim; et al. (February 2005). "Increase in scrotal temperature in laptop computer users". Hum. Reprod. 20 (2): 452–455. doi:10.1093/humrep/deh616. PMID 15591087.

匿名

検索

案内

案内

scrotum