Inmalehuman anatomy, theglans penis orpenile glans,[1] commonly referred to as theglans, (/ɡlænz/; fromLatinglans meaning "acorn")[2] is the bulbous structure at thedistal end of thehuman penis that is the human male's most sensitiveerogenous zone and primaryanatomical source ofsexual pleasure.[3][4] The glans penis is part of the malereproductive organs ofhumans and most othermammals where it may appear smooth, spiny, elongated or divided.[5] It is externally lined withmucosal tissue, which creates a smooth texture and glossy appearance. In humans, the glans is located over the distal end of thecorpora cavernosa and is a continuation of thecorpus spongiosum of the penis. At the tip is theurinary meatus and the base forms thecorona glandis. An elastic band of tissue, thefrenulum, runs across its ventral surface. In men who are notcircumcised, it is completely or partially covered by a fold of skin called theforeskin. In adults, the foreskin can generally be retracted over and past the glans manually or sometimes automatically during anerection.[6]
Diagram of the arteries of the penis and its glansThe glans penis as the expansion of the corpus spongiosum
The glans penis is a body of spongyerectile tissue that is moulded on the rounded ends of the twocorpora cavernosa penis,[9] extending farther on their upper than on their lower surfaces. It is the expanded cap of thecorpus spongiosum,[10] a sponge-like region that surrounds the maleurethra within the penis maintaining it as a viable channel forejaculation.[11] The glans is covered by astratified squamous epithelium and a dense layer ofconnective tissue equivalent to thedermis of typical skin.[12] The papillary layer of the dermis blends into the dense connective tissue forming thetunica albuginea of the corpus spongiosum behind the glans.[12] The external lining withmucosal tissue is responsible for its typical smooth texture and appearance.
The increase ofarterial flow duringerection fills the erectile tissue with blood causing the glans to grow in size and sensitivity.[13] While the penis is rigid when erect, the glans itself remains slightly softer.[14] The soft cushiony texture of the glans absorbs impact during rigorous instances of copulation.[15] The proportional size of the glans penis can vary among males. While the shape of the glans is typically acorn-like, in some men it might be wider in circumference than the shaft, giving the penis a mushroom-like appearance, while in others it might be narrower and more akin to a probe in shape.
The reason for the shape of the glans is uncertain. Some researchers suggest that it evolved to be acorn-, mushroom-, or cone-shaped, allowing it to remove any semen from previous sexual partners during copulation. However, this theory is not supported when considering the mating behaviors ofprimate relatives, which differ.[16][17]
At the summit of the glans is the slit-like vertical external urethral orifice, called theurinary meatus, through which urine,semen andpre-ejaculatory fluid exit the penis. The circumference of the base of the glans forms a rounded projecting border, thecorona glandis, overhanging a deep retroglandulargroove known as thecoronal sulcus. Behind the corona is the neck of the penis, which separates the glans and the penile shaft. Ventrally, the two glans wings merge on the midline forming theseptum glandis and a triangle or a V-shaped area under it. Thefrenulum is the highlyvascularized elastic band of tissue located on the underside of the glans that connects the foreskin to the head of the penis. The frenulum is supple enough to allow the retraction of the foreskin over the glans and pull it back when the erection is gone.[18] In flaccid state, it tightens to narrow the foreskin opening.[19]
The glans and the frenulum areinnervated by the bilateraldorsal nerve of the penis and theperineal nerve, both divisions of thepudendal nerve.[20] Branches of the dorsal nerve extend through the glans ventrolaterally displaying a three-dimensional innervation pattern.[20][21] The main branches form smaller bundles of nerves that expand outwards into the tissue of the glans.[20] The rich innervation of the glans penis reveals its function as a primary anatomical source of male sexual pleasure.[4][21][22] Yang & Bradley argue; "the distinct pattern of innervation of the glans emphasizes its role as a sensory structure".[4] While Yang & Bradley's (1998) report "showed no areas in the glans to be more densely innervated than others.",[4] Halata & Munger (1986) report that the density of several nerve terminals is greatest in the corona glandis.[12]
Halata & Spathe (1997) reported: "The glans penis contains a predominance offree nerve endings, numerous genitalend bulbs and rarelyPacinian andRuffinian corpuscles.Merkel nerve endings andMeissner's corpuscles (mechanoreceptors typically found in thickglabrous skin) are not present".[23] The genital end bulbs, which are present throughout the glans, are most numerous in the corona and near the frenulum.[12] Simple, Pacinian and Ruffinian corpuscles are identified predominantly in the corona glandis. The most numerous nerve terminals are free nerve endings present in almost everydermal papilla of the glans, as well as scattered throughout the deeperdermis.[12]
The glans penis receives blood from theinternal pudental artery through its branch, thedorsal artery of the penis, which also supplies the foreskin, and thepenile shaft.[24] Behind thecorona, the terminal branches of the dorsal arteriesanastomose with the axial arteries through perforating branches before they end in the glans.[25] Branches of the dorsal artery curve around each side of the distal shaft to enter the glans and the frenulum ventrally.[26] Venous drainage of the penis begins at the base of the glans. Small tributaries deriving from the corona form a venous plexus at the neck of the penis, known as the retro-coronal, or retro-balanic, plexus.[27] Smaller paired venules run into the frenulum and the glans from its ventral surface.[28] The deep dorsal vein, one of the twodorsal veins of the penis, serves as a common vessel receiving blood drained from the glans and the twocorpora cavernosa through the circumflex veins that surround them.[27][29]
The glans is completely or partially covered by a double-layered fold of skin, known as theforeskin. In adults, glans exposure can be easily achieved by manual retraction of the foreskin and sometimes automatically duringerection. The degree of automatic foreskin retraction varies considerably depending on the foreskin length. The foreskin can be characterized as long when the preputial orifice extends beyond the glans during erection, or medium when the orifice is located around the meatus.[30] The primary purpose of the foreskin is considered to be the covering of the glans and theurinary meatus,[31][32] while also maintaining themucosa in a moist environment.[33]
Foreskin rectractability gradually increases with age. Ininfancy the foreskin is fused to the glans.[34] It remains non-retractable in earlychildhood and it continues to be tight duringpreadolescence.[35] The skin begins to loosen up significantly duringpuberty allowing the glans to be completely exposed when needed. By the age of eighteen, most boys will have a fully retractable foreskin.[36]
In some cases, forcultural,medical, orprophylactic reasons, some men undergocircumcision or were circumcised as infants, a procedure in which the foreskin is partially or completely removed from the penis.[19] The glans of circumcised men remains fully exposed and dry. Several studies have suggested that, generally, the glans of both circumcised and uncircumcised penises are equally sensitive.[37][38][39]
Although the sex of the infant isdetermined from the moment ofconception,[7] the complete external differentiation of the organs begins about eight or nine weeks after conception.[42] Some sources state that the process will be completed by the twelfth week,[43][44] while others state that it is clearly evident by the thirteenth week and that the sex organs are fully developed by the sixteenth week.[8]
Both the penis and clitoris develop from the sametissues that become the glans andshaft of the penis and this shared embryonic origin makes these two organshomologous (different versions of the same structure).[8][45] In thefemale fetus the absence of testosterone will stop the growth of the phallus causing the tubercle to shrink and form the clitoris. In themale fetus the presence of a Y chromosome leads to the development of thetestes, which secrete a large amount of hormones called androgens. These hormones will cause themasculinization of the phenotypically indifferent organs.[7] When exposed to testosterone, the genital tubercle elongates to form thepenis. By fusion of theurogenital folds—elongated spindle-shaped structures that contribute to the formation of theurethral groove on the belly aspect of the genital tubercle—theurogenital sinus closes completely to form thespongy urethra and the labioscrotal swellings unite to form thescrotum.[46][8] The secretion of testosterone during this phase plays a decisive role in the final shaping of the penis. After birth, testosterone levels drop significantly untilpuberty.
Theepithelium of the glans penis consists ofmucosal tissue. Birleyet al. report that excessivewashing with soap may dry the mucous membrane which covers the glans penis and cause non-specificdermatitis. The condition is described as an inflammation of the skin, often caused by an irritating substance or acontact allergy. Sensitivity to chemicals in certain products can cause an allergic reaction, including irritation,itching andrash.[47]
Inflammation of the glans penis is known asbalanitis. It is a treatable condition that occurs in about 3–11% of males (up to 35% of diabetic males). Edwards reported that it is generally more common in males who have poorhygiene habits or have not been circumcised. It has many causes, including irritation or infection with a wide variety ofpathogens. Symptoms of balanitis may appear suddenly or develop gradually. They might include pain, irritation, redness or red patches on the glans penis. Careful identification of the cause with the aid of patient history, physicalexamination, swabs and cultures, and biopsy are essential in order to determine the proper treatment.[48]
Themeatus (opening) of the urethra located at the tip of the glans might become subject tomeatal stenosis, a condition mostly seen as a late complication of circumcision. It occurs in about 2–20% of circumcised boys[49][50] and it is rarely seen in uncircumcised men.[51] It is characterized by a narrowing of the meatus, which might cause sudden or often urges to urinate and burning during the process.[51]
For some individuals who experience difficulty in achieving full glanular engorgement of glans penis, they may be diagnosed with soft glans syndrome (glans insufficiency syndrome). It is often undiagnosed in the general population due to the lack of a standardized nomenclature.[52][53]
Malefelids are able tourinate backwards by curving the tip of the glans penis backward.[54][55] In cats, the glans penis is covered with spines.Penile spines also occur on the glans of male and femalespotted hyenas.[54] In male dogs the glans penis is smooth and consists of two parts called thebulbus glandis andpars longa glandis.[56] The glans of afossa's penis extends about halfway down the shaft andis spiny except at the tip. In comparison, theglans of felids is short and spiny, while that ofviverrids is smooth and long.[57]
The glans penis of themarsh rice rat is long and robust,[58] averaging 7.3 mm (0.29 in) long and 4.6 mm (0.18 in) broad.[59]Winkelmann's mouse can most readily be distinguished from its close relatives by its partially corrugated glans penis.[60] InThomasomys ucucha, the glans penis is rounded, short, and small and is superficially divided into left and right halves by a trough at the top and a ridge at the bottom. Most of the glans is covered with spines, except for an area near the tip.[61] The glans penis of a malecape ground squirrel is large with a prominentbaculum.[62]
The shape of the glans varies among differentmarsupial species.[73][74][75] In most marsupials, the glans is divided, but malemacropods have an undivided glans penis.[5]
^Olausson, Håkan; Wessberg, Johan; Morrison, India (2016).Affective Touch and the Neurophysiology of CT Afferents.Springer Science+Business Media. p. 305.ISBN978-1-4939-6418-5....the most pleasurable of all body parts when stimulated sexually: the glans (or tip) of the penis.
^abcdYang, C. C.; W.E. Bradley (July 1998). "Neuroanatomy of the penile portion of the human dorsal nerve of the penis".British Journal of Urology.82 (1):109–13.doi:10.1046/j.1464-410x.1998.00669.x.PMID9698671.
^Keenan-Lindsay, Lisa; Sams, Cheryl; O'Connor, Constance; Perry, Shannon; Hockenberry, Marilyn; Leonard Lowdermilk, Deitra; Wilson, David (December 17, 2021).Maternal Child Nursing Care in Canada.Elsevier Health Sciences. p. 501.ISBN978-0-323-75920-5.
^Hsu, Geng-Long; Lu, Hsiu-Chen (2018-01-01),"Penis Structure—Erection", in Skinner, Michael K. (ed.),Encyclopedia of Reproduction (Second Edition), Oxford: Academic Press, pp. 367–375,ISBN978-0-12-815145-7, retrieved2023-07-06
^HSU, G‐L., et al. "The distribution of elastic fibrous elements within the human penis." BJU International 73.5 (1994): 566-571.
^Velazquez, Elsa F.; Bock, Adelaida; Soskin, Ana; Codas, Ricardo; Arbo, Manuel; Cubilla, Antonio L. (2003). "Preputial variability and preferential association of long phimotic foreskins with penile cancer: An anatomic comparative study of types of foreskin in a general population and cancer patients".The American Journal of Surgical Pathology.27 (7):994–998.doi:10.1097/00000478-200307000-00015.ISSN0147-5185.PMID12826892.S2CID34091663.
^Clifford B., Bleustein; Fogarty, James D.; Eckholdt, Haftan; Arezzo, Joseph C.; Melman, Arnold (April 2005). "Effect of neonatal circumcision on penile neurologic sensation".Urology.65 (4):773–777.doi:10.1016/j.urology.2004.11.007.PMID15833526.
^Payne, Kimberley; Thaler, Lea; Kukkonen, Tuuli; Carrier, Serge; Binik, Yitzchak (May 2007). "Sensation and sexual arousal in circumcised and uncircumcised men".Journal of Sexual Medicine.4 (3):667–674.doi:10.1111/j.1743-6109.2007.00471.x.PMID17419812.
^Sloane, Ethel (2002). Biology of Women. Cengage Learning.ISBN978-0-7668-1142-3. Archived from the original on 13 June 2013. Retrieved 27 October 2015.
^Bradley, R.D.; Schmidley, D.J. (1987). "The glans penes and bacula in Latin American taxa of thePeromyscus boylii group".Journal of Mammalogy.68 (3):595–615.doi:10.2307/1381595.JSTOR1381595.
