Scrotum - wikipedia Scrotum For the obsolete dinosaur fossil name, see Megalosaurus § `` Scrotum humanum ''. Scrotum Human scrotum in a relaxed state ( left ) and a tense state ( right ) Details 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 Latin Scrotum MeSH A05. 360.444. 661 Dorlands / Elsevier 12726162 TA A09. 4.03. 001 FMA 18252 Anatomical terminology ( edit on Wikidata ) The scrotum is an anatomical male reproductive structure that consists of a suspended dual - chambered sack of skin and smooth muscle that is present in most terrestrial male mammals and located under the penis. One testis is typically lower than the other, which functions to avoid compression in the event of impact. The perineal raphe is a small, vertical, slightly raised ridge of scrotal skin under which is found the scrotal septum. It appears as a thin longitudinal line that runs front to back over the entire scrotum. The scrotum contains the external spermatic fascia, testes, epididymis and ductus deferens. It is a distention of the perineum and carries some abdominal tissues into its cavity including the testicular artery, testicular vein and pampiniform plexus. In humans and some other mammals, the scrotum becomes covered with pubic hair at puberty. The scrotum will usually tighten during penile erection and when exposed to cold temperature. The scrotum is biologically homologous to the labia majora in females. Although present in most mammals, the external scrotum is absent in streamlined marine mammals, such as whales and seals, as well as in some lineages of land mammals, such as the afrotherians, xenarthrans, and numerous families of bats, rodents, and insectivores. Contents 1 Structure 1.1 Innervation 1.2 Blood supply 1.3 Integument 1.4 Lymphatic system 2 Development 2.1 Genital homology between sexes 2.2 Asymmetry 2.3 Scrotal growth and puberty 3 Internal structure 4 Function 5 Clinical significance 6 Diseases and conditions 7 See also 8 Bibliography 9 References Structure Innervation Nerve Surface 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 Blood supply Blood vessels Anterior scrotal artery Posterior scrotal artery Testicular artery Integument Skin associated tissues Hair Sebaceous glands Apocrine glands Smooth muscle The skin on the scrotum is more highly pigmented compared to the rest of the body. The septum is a connective tissue membrane dividing the scrotum into two cavities. Lymphatic system The scrotum lymph drains initially into the superficial inguinal lymph nodes, this then drains into the deep inguinal lymph nodes. The deep inguinal lymph nodes drain into the common iliac which ultimately releases lymph into the cisterna chyli. Lymphatic vessels Superficial inguinal lymph nodes Popliteal lymph nodes Popliteal lymph nodes Development Stages in the development of the male external genitalia. Main article : Development of the reproductive system Genital homology between sexes Main article : Sexual homology Male sex hormones are secreted by the testes later in embryonic life to cause the development of secondary sex organs. The scrotum is developmentally homologous to the labia minora and labia majora. The raphe does not exist in females. Reproductive organs and tissues develop in females and males begin during the fifth week after fertilization. The gonadal ridge grows behind the peritoneal membrane. By the sixth week, string - like tissues called primary sex cords form within the enlarging gonadal ridge. Externally, a swelling called the genital tubercule appears over the cloacal membrane. Up until the eighth week after fertilization, the reproductive organs do not appear to be different between the male and female and are called in - differentiated. 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 scrotal raphe is formed when the embryonic, urethral groove closes by week 12. 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. 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. Internal structure Additional tissues and organs reside inside the scrotum and are described in more detail in the following articles : Appendix of epididymidis Cavity of tunical albuginea Cremaster muscle Dartos Ductus Deferens Efferent ductules Epididymis Leydig cell Lobule of testes Paradidymis Rete testes Scrotal septum Seminiferous tubule Sertoli cell Spermatic cord Testes Tunica albuginea of testis Tunica vaginalis parietal layer Tunica vaginalis visceral layer Tunica vasculosa testis Vas deferens Function Image showing musculature and inner workings of the scrotum. The scrotum regulates the temperature of the testes and maintains it at 35 degrees Celsius ( 95 degrees Fahrenheit ), i.e. two degrees below the body temperature of 37 degrees Celsius ( 98.6 degrees Fahrenheit ). Higher temperatures affect spermatogenesis 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 ). 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. 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. Animals that have stately movements -- such as elephants, whales, and marsupial moles -- have internal testes and no scrotum. Unlike placental mammals, male marsupials have a scrotum that is anterior to the penis. In some sex positions, such as doggystyle the scrotum may provide friction for the clitoris, and may subsequently serve as an impetus for sexual pleasure or orgasm in the woman. Clinical significance A study has indicated that use of a laptop computer positioned on the lap can negatively affect sperm production. Diseases and conditions The scrotum and its contents can develop diseases or incur injuries. These include : Candidiasis ( yeast infection ) sebaceous cyst epidermal cyst hydrocele hematocele Molluscum contagiosum spermatocele Paget 's disease of the scrotum varicocele inguinal hernia epididymo - orchitis testicular torsion genital warts testicular cancer dermatitis undescended testes Chyloderma mumps scabies herpes pubic lice Chancroid ( Haemophilus ducreyi ) Chlamydia ( Chlamydia trachomatis ) Gonorrhea ( Neisseria gonorrhoeae ) Granuloma inguinale or ( Klebsiella granulomatis ) Syphilis ( Treponema pallidum ) scrotum eczema scrotal psoriasis disease Riboflavin deficiency See also This article uses anatomical terminology ; for an overview, see Anatomical terminology. Scrotal infusion, a temporary form of body modification Sex organ Retroperitoneal lymph node dissection Testicular self - examination Bibliography Books This article incorporates text in the public domain from the 20th edition of Gray 's Anatomy ( 1918 ) Van De Graaff, Kent M. ; Fox, Stuart Ira ( 1989 ). Concepts of Human Anatomy and Physiology. Dubuque, Iowa : William C. Brown Publishers. ISBN 0697056759. Elson, Lawrence ; Kapit, Wynn ( 1977 ). The Anatomy Coloring. New York, New York : Harper & Row. ISBN 0064539148. `` Gross Anatomy Image ''. Medical Gross Anatomy Atlas Images. University of Michigan Medical School. 1997. Retrieved 2015 - 02 - 23. Berkow, MD, editor, Robert ( 1977 ). The Merck Manual of Medical Information ; Home Edition. Whitehouse Station, New Jersey : Merck Research Laboratories. ISBN 0911910875. CS1 maint : Multiple names : authors list ( link ) CS1 maint : Extra text : authors list ( link ) References Wikimedia Commons has media related to Scrotum. ^ Jump up to : Anthony F. Bogaert, `` Genital asymmetry in men '', Human Reproduction vol. 12 no. 1 pp. 68 -- 72, 1997. PMID 9043905. Jump up ^ `` Scrotum ''. National Institutes of Health. Retrieved 6 January 2011. Jump up ^ Lovegrove, B.G. 2015. `` Cool sperm : why some placental mammals have a scrotum. '' Journal of Evolutionary Biology. 27 ( 5 ) : 801 - 814. doi : 10.1111 / jeb. 12373 Jump up ^ Moore, Keith ; Anne Agur ( 2007 ). Essential Clinical Anatomy, Third Edition. Lippincott Williams & Wilkins. p. 132. ISBN 0 - 7817 - 6274 - X. ^ Jump up to : Elson 1977. Jump up ^ `` Scrotum ''. Encyclopædia Britannica. Retrieved 2015 - 02 - 24. Jump up ^ `` VIII. The Lymphatic System. 5. The Lymphatics of the Lower Extremity. Gray, Henry. 1918. Anatomy of the Human Body. ''. Retrieved 2015 - 02 - 24. Jump up ^ Van de Graaff 1989, p. 927 - 931. Jump up ^ Gallup, G.G., Jr., Finn, M.M., & Sammis, B. `` On the origin of descended scrotal testicles : The activation hypothesis., Evolutionary Psychology, 7, 2009, p. 517 - 524. ^ Jump up to : Van de Graaff 1989, p. 935. ^ Jump up to : Van de Graaff 1989, p. 936. Jump up ^ `` Science : Bumpy lifestyle led to external testes - 17 August 1996 - New Scientist ''. New Scientist. Retrieved 2007 - 11 - 06. Jump up ^ Hugh Tyndale - Biscoe ; Marilyn Renfree ( 30 January 1987 ). Reproductive Physiology of Marsupials. Cambridge University Press. ISBN 978 - 0 - 521 - 33792 - 2. Jump up ^ Libbie Henrietta Hyman ( 15 September 1992 ). Hyman 's Comparative Vertebrate Anatomy. University of Chicago Press. pp. 583 --. ISBN 978 - 0 - 226 - 87013 - 7. Jump up ^ Menna Jones ; Chris R. Dickman ; Michael Archer ( 2003 ). Predators with Pouches : The Biology of Carnivorous Marsupials. Csiro Publishing. ISBN 978 - 0 - 643 - 06634 - 2. Jump up ^ Jones, Richard ( 2013 ). Human Reproductive Biology. Academic Press. p. 74. The rear - entry position of mating may allow the scrotum to stimulate the clitoris and, in this way, may produce an orgasm... Jump up ^ `` Laptops may damage male fertility ''. BBC News. 2004 - 12 - 09. Retrieved 2012 - 01 - 30. Jump up ^ Sheynkin, Yefim ; et al. ( February 2005 ). `` Increase in scrotal temperature in laptop computer users ''. Hum. Reprod. 20 ( 2 ) : 452 -- 455. PMID 15591087. doi : 10.1093 / humrep / deh616. Jump up ^ `` Paget 's disease of the scrotum Symptoms, Diagnosis, Treatments and Causes ''. RightDiagnosis.com. Retrieved 2015 - 02 - 24. Jump up ^ `` Common scrotal skin diseases ''. TCMWell. Retrieved 2015 - 02 - 24. ^ Jump up to : TCMwell. Male reproductive system Internal Seminal tract Testes layers Tunica vaginalis Tunica albuginea Tunica vasculosa Appendix Mediastinum Lobules Septa Leydig cell Sertoli cell Blood -- testis barrier Spermatogenesis Spermatogonium Spermatocytogenesis Spermatocyte Spermatidogenesis Spermatid Spermiogenesis Spermatozoon Other Seminiferous tubules Tubuli seminiferi recti Rete testis Efferent ducts Epididymis Appendix Stereocilia Paradidymis Spermatic cord Vas deferens Ampulla Ejaculatory duct Accessory glands Seminal vesicles excretory duct Prostate Urethral crest Seminal colliculus Prostatic utricle Ejaculatory duct Prostatic sinus Prostatic ducts Bulbourethral glands External Penis root Crus Bulb Fundiform ligament Suspensory ligament body Corpus cavernosum Corpus spongiosum glans Foreskin Frenulum Corona fascia superficial deep Tunica albuginea Septum of the penis Urinary tract Internal urethral orifice Urethra Prostatic Intermediate Spongy Navicular fossa External urethral orifice Lacunae of Morgagni Urethral gland Scrotum layers skin Dartos External spermatic fascia Cremaster Cremasteric fascia Internal spermatic fascia Perineal raphe Scrotal septum Outline of human sexuality Physiology and biology Erection Insemination Intersex Libido Orgasm Female and male ejaculation Pre-ejaculate Pregnancy Sexual arousal Health and education Birth control Condom Masters and Johnson Reproductive medicine Andrology Gynaecology Urology Safe sex Sex education Sex therapy Sexology Sexual dysfunction Erectile dysfunction Hypersexuality Hyposexuality Sexual medicine Sexual surrogate Sexually transmitted infection Identity and diversity Gender binary Gender identity Men who have sex with men Sexual identity Sexual orientation Women who have sex with women Law Age of consent Criminal transmission of HIV Child sexual abuse Incest Indecent exposure Obscenity Sexual abuse Rape Sexual assault Sexual harassment Sexual misconduct Sexual violence History Blue Movie Counterculture of the 1960s Feminist sex wars Golden Age of Porn History of erotic depictions `` Porno chic '' Sexual revolution Relationships and society Anarchism and love / sex Extramarital sex Family planning Flirting Marriage Modesty Paraphilia Polyamory Premarital sex Promiscuity Romance Sexual abstinence Sexual addiction Sexual attraction Sexual capital Sexual ethics Sexual objectification Sexual slang By country Ancient Rome China India Japan Philippines South Korea United States Sexual activities Anal sex Bareback BDSM Child sex Coprophilia Creampie Gang bang Emetophilia Fetishism Fingering Fisting Group sex Masturbation Mechanics of sex Nipple stimulation Non-penetrative sex Facial Foot fetishism Footjob Frot Handjob Mammary intercourse Sumata Oral sex 69 Anilingus Cunnilingus Fellatio Irrumatio Orgasm control Paraphilia Pompoir Quickie Sex positions Sexual fantasy Sexual fetishism Sexual intercourse Foreplay Sexual penetration Sexual sublimation Swinging Tribadism Urethral intercourse Urolagnia Virtual sex Cybersex Dirty talk Wet T - shirt contest Zoophilia Sex industry Red - light district Adult video games Erotica Pornography Film actor Prostitution Survival sex Sex museum Sex shop Sex tourism Child Female Sex worker Sex toy doll Strip club Webcam model Religion and sexuality Buddhism Christian demonology Daoism Islam Mormonism Sex magic Portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Scrotum&oldid=801873041 '' Categories : Wikipedia articles incorporating text from the 20th edition of Gray 's Anatomy ( 1918 ) Mammal male reproductive system Integumentary system Human male reproductive system Sex organs Scrotum Testicle Hidden categories : Wikipedia pages move - protected due to vandalism Medicine infobox template using GraySubject or GrayPage Medicine infobox template using Dorlands parameter CS1 maint : Multiple names : authors list CS1 maint : Extra text : authors list Talk Contents About Wikipedia Afrikaans Aragonés ܐܪܡܝܐ Avañe'ẽ বাংলা Bân - lâm - gú Беларуская Беларуская ( тарашкевіца ) ‎ Български Bosanski Català Čeština Dansk Deutsch ދިވެހިބަސް Ελληνικά Español Esperanto Euskara فارسی Français Gaeilge Galego 한국어 Հայերեն Hrvatski Ido Bahasa Indonesia Íslenska Italiano עברית Basa Jawa Kapampangan Қазақша Latina Latviešu Lietuvių Limburgs Magyar Македонски മലയാളം مصرى Mìng - dĕ̤ng - ngṳ̄ Nederlands 日本 語 Norsk Norsk nynorsk Occitan Plattdüütsch Polski Português Română Runa Simi Русский Scots Simple English Slovenčina Slovenščina کوردی Српски / srpski Srpskohrvatski / српскохрватски Basa Sunda Suomi Svenska Tagalog ไทย Türkçe Українська Vahcuengh Tiếng Việt 粵語 中文 Edit links This page was last edited on 22 September 2017, at 13 : 11. 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Question: where is the scrotum located on a male
Answer: under the penis