Glans penis

Glans penis

Glans penis (dorsal view)

Glans penis (ventral view)
Details
Artery Urethral artery
Identifiers
Latin Glans penis
TA A09.4.01.007
FMA 18247

Anatomical terminology

The male anatomy showing the location of the glans penis.

The glans penis (or simply glans, /ɡlænz/)[1] is the sensitive bulbous structure at the distal end of the human penis. The glans is anatomically homologous to the clitoral glans of the human female.

Typically, the glans is completely or partially covered by the foreskin, except in men who have been circumcised. The foreskin can generally be retracted over and past the glans, and may automatically retract during an erection.

The glans is more commonly known as the "head" or the "tip" of the penis. The medical name comes from the Latin words glans ('acorn') and penis ('of the penis') – the Latin genitive of this word has the same form as the nominative.

Medical considerations

The meatus (opening) of the urethra is located at the tip of the glans penis. In circumcised infants, the foreskin no longer protects the meatal area of the glans; consequently, when wearing diapers, there may be greater risk of developing meatitis, meatal ulceration, or meatal stenosis.[2]

The epithelium of the glans penis is mucocutaneous tissue.[3] Birley et al. report that excessive washing with soap may dry the mucous membrane that covers the glans penis and cause non-specific dermatitis.[4]

Inflammation of the glans penis is known as balanitis. It occurs in 3–11% of males, and up to 35% of diabetic males. Edwards reported that it is generally more common in males who have poor hygiene habits or have not been circumcised.[5] It has many causes, including irritation, or infection with a wide variety of pathogens. Careful identification of the cause with the aid of patient history, physical examination, swabs and cultures, and biopsy are essential in order to determine the proper treatment.[5]

Anatomical details

The glans penis is the expanded cap of the corpus spongiosum. It is moulded on the rounded ends of the corpora cavernosa penis, extending farther on their upper than on their lower surfaces. At the summit of the glans is the slit-like vertical external urethral orifice. The circumference of the base of the glans forms a rounded projecting border, the corona glandis, overhanging a deep retroglandular sulcus (the coronal sulcus), behind which is the neck of the penis. The proportional size of the glans penis can vary greatly. On some penises it is much wider in circumference than the shaft, giving the penis a mushroom-like appearance, and on others it is narrower and more akin to a probe in shape.

The foreskin maintains the mucosa in a moist environment.[6] In males who have been circumcised, the glans is permanently exposed and dry. Szabo and Short found that the glans of a circumcised penis does not develop a thicker keratinization layer.[7] Several studies have suggested that the glans is equally sensitive in circumcised and uncircumcised males,[8][9][10][11] while others have reported that it is more sensitive in males who are not circumcised.[12][13]

Halata & Munger (1986) report that the density of genital corpuscles is greatest in the corona glandis,[14] while Yang & Bradley (1998) report that their study "showed no areas in the glans to be more densely innervated than others."[15]

Halata & Spathe (1997) reported that "the glans penis contains a predominance of free nerve endings, numerous genital end bulbs and rarely Pacinian and Ruffinian corpuscles. Merkel nerve endings and Meissner's corpuscles are not present."[3]

Yang & Bradley argue that "the distinct pattern of innervation of the glans emphasizes the role of the glans as a sensory structure".[15]

In other animals

The glans of a fossa's penis extends about halfway down the shaft and is spiny except at the tip. In comparison, the glans of felids is short and spiny, while that of viverrids is smooth and long.[16] Male felids urinate backwards by curving the tip of the glans penis backward.[17][18]

The shape of the glans varies among different marsupial species.[19][20][21] In most marsupials, the glans is divided, but male macropods have an undivided glans penis.[22]

The glans penis of the marsh rice rat is long and robust,[23] averaging 7.3 mm (0.29 in) long and 4.6 mm (0.18 in) broad.[24]

In Thomasomys 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.[25]

Winkelmann's mouse can most readily be distinguished from its close relatives by its partially corrugated glans penis.[26]

When erect, the glans of a horse's penis increases by 3 to 4 times. The urethra opens within the urethral fossa, a small pouch at the distal end of the glans.[27] Unlike the human glans, the glans of a horse's penis extends backwards on its shaft.[28][29][30][31][32][33][34][35][36]

Males of Racey's pipistrelle bat have a narrow, egg-shaped glans penis.[37]

The glans penis of a male cape ground squirrel is large with a prominent baculum.[38]

See also

References

  1. ↑ OED 2nd edition, 1989.
  2. ↑ Freud, Paul (August 1947). "The ulcerated urethral meatus in male children". The Journal of Pediatrics. 31 (2): 131–41. doi:10.1016/S0022-3476(47)80098-8. PMID 20256409. Retrieved 2006-07-07.
  3. 1 2 Halata, Zdenek; A. Spaethe (1997). "Sensory innervation of the human penis". Advances in experimental medicine and biology. Advances in Experimental Medicine and Biology. 424: 265–6. doi:10.1007/978-1-4615-5913-9_48. ISBN 978-0-306-45696-1. PMID 9361804. Retrieved 2006-07-07.
  4. ↑ Birley, H. D.; M .M. Walker; G. A. Luzzi; R. Bell; D. Taylor-Robinson; M. Byrne; A. M. Renton (October 1993). "Clinical features and management of recurrent balanitis; association with atopy and genital washing". Genitourinary Medicine. 69 (5): 400–3. doi:10.1136/sti.69.5.400. PMC 1195128Freely accessible. PMID 8244363.
  5. 1 2 Edwards, Sarah (June 1996). "Balanitis and balanoposthitis: a review". Genitourinary Medicine. 72 (3): 155–9. doi:10.1136/sti.72.3.155. PMC 1195642Freely accessible. PMID 8707315.
  6. ↑ Prakash, Satya; Raghuram Rao; K. Venkatesan; S. Ramakrishnan (July 1982). "Sub-Preputial Wetness--Its Nature". Annals of National Medical Science (India). 18 (3): 109–112.
  7. ↑ Szabo, Robert; Roger V. Short (June 2000). "How does male circumcision protect against HIV infection?". British Medical Journal. 320 (7249): 1592–4. doi:10.1136/bmj.320.7249.1592. PMC 1127372Freely accessible. PMID 10845974. Retrieved 2006-07-07.
  8. ↑ Masters, William H.; Virginia E. Johnson (1966). Human Sexual Response. Boston: Little, Brown & Co. pp. 189–91. ISBN 0-316-54987-8. (excerpt accessible here )
  9. ↑ Bleustein, Clifford B.; James D. Fogarty; Haftan Eckholdt; Joseph C. Arezzo; Arnold Melman (April 2005). "Effect of neonatal circumcision on penile neurologic sensation". Urology. 65 (4): 773–7. doi:10.1016/j.urology.2004.11.007. PMID 15833526.
  10. ↑ Bleustein, Clifford B.; Haftan Eckholdt; Joseph C. Arezzo; Arnold Melman (April 26 – May 1, 2003). "Effects of Circumcision on Male Penile Sensitivity". American Urological Association 98th Annual Meeting. Chicago, Illinois.
  11. ↑ 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. PMID 17419812.
  12. ↑ Sorrells, Morris L.; Snyder, James L.; Reiss, Mark D.; Eden, Christopher; Milos, Marilyn F.; Wilcox, Norma; Van Howe, Robert S. (April 2007). "Fine-touch pressure thresholds in the adult penis". British Journal of Urology International. 99 (4): 864–869. doi:10.1111/j.1464-410X.2006.06685.x. PMID 17378847.
  13. ↑ Yang, DM; Lin H; Zhang B; Guo W (April 2008). "Circumcision affects glans penis vibration perception threshold". Zhonghua Nan Ke Xue. 14 (4): 328–330. PMID 18481425.
  14. ↑ Halata, Zdenek; Bryce L. Munger (April 1986). "The neuroanatomical basis for the protopathic sensibility of the human glans penis". Brain Research. 371 (2): 205–30. doi:10.1016/0006-8993(86)90357-4. PMID 3697758.
  15. 1 2 Yang, 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. PMID 9698671.
  16. ↑ Köhncke, M.; Leonhardt, K. (1986). "Cryptoprocta ferox" (PDF). Mammalian Species (254): 1–5. Retrieved 19 May 2010.
  17. ↑ Reena Mathur (2010). Animal Behaviour 3/e. Rastogi Publications. ISBN 978-81-7133-747-7. Retrieved 10 February 2013.
  18. ↑ R. F. Ewer (1973). The Carnivores. Cornell University Press. pp. 116–. ISBN 978-0-8014-8493-3. Retrieved 8 February 2013.
  19. ↑ Australian Mammal Society (December 1978). Australian Mammal Society. Australian Mammal Society. pp. 73–. Retrieved 25 December 2012.
  20. ↑ Wilfred Hudson Osgood; Charles Judson Herrick (1921). A monographic study of the American marsupial, Caēnolestes ... University of Chicago. pp. 64–. Retrieved 25 December 2012.
  21. ↑ The Urologic and Cutaneous Review. Urologic & Cutaneous Press. 1920. pp. 677–. Retrieved 25 December 2012.
  22. ↑ Renfree, Marilyn; Hugh Tyndale-Biscoe (1987-01-30). Reproductive Physiology of Marsupials. Cambridge University Press. ISBN 9780521337922. Retrieved 5 May 2013.
  23. ↑ Hooper and Musser, 1964, p. 13
  24. ↑ Hooper and Musser, 1964, table 1
  25. ↑ Voss, 2003, p. 11
  26. ↑ Bradley, R.D.; Schmidley, D.J. (1987). "The glans penes and bacula in Latin American taxa of the Peromyscus boylii group". Journal of Mammalogy. 68 (3): 595–615. doi:10.2307/1381595. JSTOR 1381595.
  27. ↑ "The Stallion: Breeding Soundness Examination & Reproductive Anatomy". University of Wisconsin-Madison. Archived from the original on 2007-07-16. Retrieved 7 July 2007.
  28. ↑ Mating Males: An Evolutionary Perspective on Mammalian Reproduction. Cambridge University Press. 30 June 2012. ISBN 978-1-107-00001-8. Retrieved 5 May 2013.
  29. ↑ McCurnin's Clinical Textbook for Veterinary Technicians - Joanna M Bassert, Dennis M McCurnin - Google Boeken. Books.google.com. Retrieved 2013-08-16.
  30. ↑ Horseman's Veterinary Encyclopedia, Revised and Updated - Equine Research - Google Boeken. Books.google.com. 2005-07-01. Retrieved 2013-08-16.
  31. ↑ Equine Clinical Medicine, Surgery and Reproduction - Graham Munroe BVSc (Hons) PhD Cert EO DESM Dip ECVS FRCVS, Scott Weese DVM DVSc DipACVIM - Google Boeken. Books.google.com. 2011-03-15. Retrieved 2013-08-16.
  32. ↑ Veterinary Anatomy of Domestic Mammals: Textbook and Colour Atlas - Google Boeken. Books.google.com. Retrieved 2013-08-16.
  33. ↑ Horse Conformation: Structure, Soundness, and Performance - Equine Research - Google Boeken. Books.google.com. Retrieved 2013-08-16.
  34. ↑ The Horse - Google Boeken. Books.google.com. Retrieved 2013-08-16.
  35. ↑ Comparative Reproductive Biology - Heide Schatten, Gheorghe M. Constantinescu - Google Boeken. Books.google.com. 2008-03-21. Retrieved 2013-08-16.
  36. ↑ Equine Reproduction - Google Boeken. Books.google.com. Retrieved 2013-08-16.
  37. ↑ Bates et al., 2006, pp. 306–307
  38. ↑ Skurski, D., J. Waterman. 2005. "Xerus inauris", Mammalian Species 781:1-4.
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