The penis and foreskin: Preputial anatomy and sexual function

The penis and foreskin: Preputial anatomy and sexual function

This directory contains academic articles and discussions about preputial anatomy, dimensions, immunological functions, innervation, vascularity, sexual function, and the effects of circumcision. The articles are indexed in chronological order of publication.

In extensive reviews of the world medical literature, medical historian Frederick M. Hodges, D. Phil. (Oxon), revealed long forgotten European and American research starting from 1860, confirming that this information is not new, but simply has been forgotten in circumcising countries.1-7,9,10,12-18

See also Anatomy of the Penis and Mechanics of Intercourse (Circumcision Information Pages).

Introduction

Musculature. The prepuce has a sheath of smooth muscle tissue inside the skin which is called the peripenic muscle.8,22,41 The muscle fibers are arranged in a whorl at the end of the foreskin to form a sphincter.8 The muscle fibers keep the foreskin snugly against the glans penis.22

Skin and mucosa. The outer surface of the prepuce is skin, however the inner surface is mucosal membrane although it resembles skin in appearance. There is a muco-cutaneous boundary just inside the tip of the prepuce. The prepuce normally covers the glans penis and protects it from foreign matter, friction, drying, and injury.

Sub-preputial moisture. The sub-preputial area is normally slightly moist. Taylor et al. reported finding no sweat or sebaceous glands;34, however, Fleiss et al. reported apocrine glands that produce cathepsin B, lysosyme chymotrypsin, neutrophil elastase, cytokine, and pheromones such an androsterone.39 Prostatic, vesicular, and urethral secretions also contribute moisture.23 Moisture may also be exuded through the mucosa of the foreskin.39 Indian scientists reported that the sub-preputial moisture contains lytic material.23 Lytic material has an anti-bacterial and anti-viral action.39 The natural oils lubricate, moisturize, and protect the mucosal covering of the glans penis and inner foreskin.41

Dimensions. The foreskin tissue of an infant male may appear to be quite small, but that tissue grows in the adult to be a substantial area. The prepuce is a folded double layer of skin and mucosa so it must be unfolded to determine its true size. The average size of the adult prepuce has been stated to be about 15 square inches or more or the size of a 3 x 5-inch index card. Taylor studied 22 prepuces taken from adult cadavers. Taylor reported a range of length from 4.8 to 9.3 cm with a mean length of 6.4 cm.34 Recently, Werker and colleagues evaluated the prepuce for use in reconstructive surgery.38 Werker studied prepuces taken from 8 cadavers. Werker reported a mean surface area of 46.7 square cm of the combined inner and outer layers with a range of 18.1 sq. cm to 67.5 sq. cm. The pedicle length ranged from 11.9 cm to 20 cm with a mean of 15.4 cm.38 He also reported two cases in which the prepuce was used in reconstructive surgery. In the first case a 65-year-old man had a prepuce measuring 8.5 x 7.5 cm. or 64 sq. cm. In the second case a 62-year-old man had a prepuce measuring 10 x 9 cm or 90 sq. cm.38 Werker's findings suggest that the dimensions of the prepuce may be somewhat greater than previously believed since Werker's living specimens were larger than those taken from cadavers.

Frenulum. The prepuce is usually tethered at the bottom by the frenulum. The frenulum's function is to provide pleasure by stretching during sexual intercourse. In fact, the frenulum is coloquially known as the "sex nerve" in France and perhaps throughout Europe. By destroying this stretching action, circumcision completely destroys this fundamental means of sexual pleasure in the human male. Taylor hypothesizes that stretching of the frenulum during coitus is provides a stimulus for ejaculation.47

Vascularization. As with other neurologic structures such as the brain, the tip of the prepuce is richly supplied with blood by important vascular structures.34 The glans penis receives blood through the frenular artery.33 The prepuce serves as a conduit for several important veins. Circumcision may contribute to erectile dysfunction by destroying these blood conduits.

Immunology. The prepuce is naturally equipped with several defenses against infection.23,39,41 The infant prepuce has a pronounced tight tip with a sphincter8,39,41 formed by the whorl of muscle tissue that stays closed to keep out foreign matter but opens to allow the outflow of urine. The sub-preputial wetness contains lyzosyme, a secretion that acts to destroy harmful microorganisms.23 The prepuce contains Langerhans cells which may provide resistance to HIV infection.39,41, Fleiss, Hodges, and Van Howe discuss the immunological functions of the prepuce in detail,39 as do Cold and Taylor.41

Innervation. The prepuce is profusely innervated especially near the tip in the ridged band area where the mucocutaneous boundary occurs. It is now understood that this junction is the most sensitive and erogenous part of the penis.17,18,26,31,32,34,39,41 Winkelmann explains the importance of the mucocutaneous boundary in human sexual response.18 He explains, "All biologic phenomena, including sensation, are the result of a certain statistical events. It is logical to anticipate that some individuals will have cutaneous hyperneuria, and also to expect eventually to find some individuals with actual diminution in organization of the cutaneous nerves for sensation. Certain pathologic states may be explicable on the basis of diminished or augmented cutaneous nerve supply."18 Thus, the accumulation of sensation triggers the ejaculation reflex.18 Diminution of the available nerve supply would make achievement of orgasm more difficult. The penile erection and ejaculation require the integration and proper sequencing of somatic, sympathetic, and parasympathetic innervation.26

Taylor's ridged band is located near the tip of the prepuce on the inner layer of the foreskin near the muco-cutanaeous boundary.33 The ridged band merges smoothly with the frenulum.32 Taylor states that the ridged band is sensitive to motion.42 The foreskin slides back and forth over the glans during foreplay and intercourse.30, 31 Typically, the ridged band area of the prepuce is stretched when it passes over the glans penis and, by this stretching action, the multitude of pleasure sensors in Taylor's ridged band are stimulated.

The ridged band area, which is stimulated by motion,42 is the most highly innervated18, 32 and pleasure producing21 region of the prepuce. They clearly have an important, but not yet well understood, function in human sexual response.18,32 Cold and Taylor (1999) confirmed the structure and innervation of the prepuce, and explained its importance in more detail.41

In comparison to the prepuce, the glans penis is much less innervated and sensitive.25,27 The corona (rim) is the most highly innervated part of the glans penis.25 Stimulation of the coronal area of the glans penis may trigger ejaculation.37 The prepuce of the typical complete male may protect the corona from direct stimulation during intercourse and so tends to prevent premature and unwanted ejaculation.

Erogeny and Sexual Function. Winkelmann states, "It is apparent in our material that all the bodies [nerve endings] present have coiled or serpentine form ... Such a form lends itself admirably to the perception of changes in pressure and tension in the tissue, as the coils are oriented in three dimensions."17 The prepuce of the human male is an elastic platform for the nerve endings composed of muscle fibers embedded within the skin, so the whole prepuce may be regarded as the principal organ for perceiving the sixth sense of erogeny.18,32,38 Milos and Macris31, and Warren and Bigelow,32 have described sexual functions of the prepuce.

See Foreskin Sexual Function for a fuller discussion.

Changes in behavior associated with a missing prepuce. Laumann et al. report that men who have lost their prepuce to circumcision tend to exhibit a "more elaborated set of sexual practices than do men who are not circumcised."35 Some have improperly interpreted this statement to mean that "circumcised men have more fun." However, Van Howe and Cold explain that circumcised men may have more difficulty in obtaining sexual satisfaction from intercourse—due to the loss of the fine-touch neuroreceptors in the prepuce—and so turn to other sexual practices.36

Effects on sexual and marital relations associated with a missing prepuce: Hughes reports a study in which intact (uncircumcised) males appear to enjoy better sexual compatibility in marriage which apparently contributes to marital happiness.29 Zwang states that it is more difficult for the partner to manually stimulate the circumcised male during foreplay.37 Depending on the individual, the permanently exposed glans may experience an excess of stimulation, or the wrong kind of stimulation, during intercourse which can lead to premature ejaculation (lack of "staying power") in the circumcised male.37 The tight foreshortened immobilized skin of the circumcised penis is more vulnerable to laceration, bleeding and pain during intercourse.37 39

Erectile dysfunction (impotence) is now known to be usually caused by circulatory problems. As noted above, circumcision inteferes with penile circulation by destroying several important blood vessels that provide circulation to the penis. Circumcision may also contribute to erectile dysfunction by destroying some of the erogenous sensory tissue in the prepuce that participates in the erectile response.

O'Hara and O'Hara surveyed 138 women who had experience with both circumcised male partners and intact complete male partners.42 20 of the 138 preferred circumcised male partners while 118 (85.5%) preferred intact male partners with anatomically complete penises over circumcised males. The respondents reported that circumcised partners tended to ejaculate prematurely more frequently than intact male partners.42 Some respondents commented that unaltered male partners appeared to enjoy coitus more than their circumcised counterparts.42

Other primates. Cold and McGrath described the variations in the prepuce between human males and females and other primate species, concluding from an evolutionary perspective that the prepuce is highly evolved and has a specialized function in each species.43

In summary, the prepuce is a unique specialized structure with important immunological, protective, mechanical, erogenous, and sexual functions. The prepuce is essential to normal copulation.41

Library Holdings

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  2. Krause W. Über die Nervenendigung in den Geschlechtsorganen. [On nerve endings in the sexual organs.] Ztschr f. rat. Med. 1866; 28: 86-88.
  3. Bense W. Über Nervenendigungen in den Geschlechtsorganen. [On nerve endings in the sexual organs.] Ztschr f. rat. Med 1868; 33:1-14.
  4. Dogiel AS. Die Nervenendigungen in der Schleimhaut der äußeren Genitalorgane des Menschen. [The nerve endings in the afferent mucosa of the human genital organs.] Arch f. mkr. Anat. 1893; 41: 585-612.
  5. Sala G. Untersuchungen über die Struktur der Pacini'schen Körperchen [An investigation into the structure of Pacinian corpuscles.] Anat Anz 1901: 16: 193-196.
  6. Dogiel AS. Über die Nervenendapparate in der Haut des Menschen [Nerve endings in human skin.] Ztschr f. Wiss. Zool 1903; 75: 46-111.
  7. Ruffini A. Sur les expansions nervoses de la peau [The innervation of the skin.] Rev Gen d'Histol 1905; 3: 419-540.
  8. Jefferson G. The peripenic muscle; Some observations on the anatomy of phimosis. Surgery, Gynecology, and Obstetrics (Chicago), Vol. 23 No. 2 (August 1916): Pages 177-181.
  9. Ohmori D. Über die Entwicklung der Innervation der Genital Apparatus als peripheren Aufnahme-Apparat der genitalen Reflex. [The development of innervation of the genital apparatus as peripheral receptors for the genital reflex.] Ztschr. f. d. Ges. Anat. up Entw. 1924; 70: 347-410.
  10. Bazett HC et al. Depth, distribution and probable identification in the prepuce of sensory end-organs concerned in sensations of temperature and touch; thermometric conductivity. Arch Neurol Psychiatr 27(3), 489-517. March 1932.
  11. Deibert GA. The separation of the prepuce in the human penis. Anat Rec 1933;57:387-99.
  12. Lambertini G. Documentatazioni microfotografiche, dati micrometrici e considerazioni sui corpuscoli del senso genitale dell'uomo. [Microphotographic documentation, micrometric data and considerations of human genital sensory corpuscles.] Monitore Zoologico Italiano 1934; 45(9):247-255.
  13. Lambertini G. Osservazione istologiche sui corpuscoli nervosi nei genitali maschili dei bambini fino al decimo anno di eta. [Histological observations of the genital nerve corpuscles in boys under ten years of age.] Bolletino della Societa Italiana di Biologica Sperimentale (Napoli) 1934; 9(11):1294-1297.
  14. Lambertini G, Ruffini G. Aspetti strutturali delle espansioni nervose papillari studiate nella loro differenziazione fetale nell uomo [Structural aspects of papillary innervation studied with regard to their fetal differentiation in humans]. Monitore Zoologico Italiano 1935; 46(11-12):354-364.
  15. John F. Querschnitt durch neurohistologische Erbegebnisse an der gesunden und ranken Haut des Menschen [A cross-sectional examination of neurohistological findings on healthy and diseased human skin]. Arch. f. Dermat. u. Syph. 1950; 191:515-526.
  16. Kantner, M. Studien Über den sensiblen Apparat in der Glans Penis [Study of the sensory apparatus in the glans penis]. Anat Anz 1952; 99: 159-179.
  17. Winkelmann RK. The cutaneous innervation of human newborn prepuce. Journal of Investigative Dermatology 1956 26(1) : 53-67.
  18. Winkelmann RK. The erogenous zones: Their nerve supply and significance. Proc Staff Mayo Clin 1959; 34(2): 39-47.
  19. Winkelmann, RK. Nerve Endings in Normal and Pathologic Skin. CC Thomas: Springfield, Illinois, 1960.
  20. Falliers CJ. Circumcision (letter). JAMA 1970;214(12):2194.
  21. Parkash S, Jeyakumar S, Subramanyan K, et al. Human subpreputial collection: its nature and formation. Journal of Urology 1973;110: 211-212.
  22. Lakshmanan S, Prakash S. Human prepuce: Some aspects of structure and function. Indian Journal of Surgery 1980 (44): 134-137.
  23. Prakash S, Raghuram R, Venkatesan, et al. Sub-preputial wetness - Its nature. Ann Nat Med Sci (India) 1982; 18(3): 109-112.
  24. Money J, Davison J. Adult penile circumcision: erotosexual and cosmetic sequelae. J Sex Research 1983; 19(2): 289-292.
  25. Halata Z, Munger BL. The neuroanatomic basis for the protopathic sensibility of the human glans. Brain Research 1986; 371: 205-230.
  26. Moldwin RM, Valderrama E. Immunochemical analysis of nerve distribution patterns within prepucial tissue. J Urol 1989;141(4) Part 2:499A.
  27. Halata Z, Spaethe A. Sensory innervation of the human penis. Adv Exp Med Biol 1997;424:265-6.
  28. Roehrborn CG, Lange JL, George FW, Wilson JD. Changes in amount and intracellular distribution of androgen receptor in human foreskin as a function of age. J Clin Invest 1987;79(1):44-7.
  29. Hughes G. Circumcision: another look. Ohio Medicine 1990; 86:92.
  30. Hinman F, Jr. The blood supply to preputial island flaps. J Urol 1991; 145:1232-1235.
  31. Milos M, Macris D. Circumcision: bEffects upon human sexuality. Encyclopedia of Human Sexuality (New York: Garland Pub., 1994), p. 119-122.
  32. Warren JP, Bigelow J. The case against circumcision. British Journal of Sexual Medicine, Sept/Oct 1994.
  33. Persad R, Sharma J, McTavish J, et al. Clinical presentation and pathophysiology of meatal stenosis following circumcision. Brit J Urol 1995; 75: 91-93.
  34. Taylor JR, Lockwood AP, Taylor AJ. The prepuce: Specialized mucosa of the penis and its loss to circumcision. British Journal of Urology 1996; 77: 291-295.
  35. Laumann EO, Masi CM, Zuckerman EW. Circumcision in the United States: prevalence, prophylactic effects, and sexual practice. JAMA 1997;277(13):1052-1057.
  36. Van Howe RS, Cold CJ. Advantages and disadvantages of neonatal circumcision. JAMA 1997;278:203.
  37. Zwang G. Functional and erotic consequences of sexual mutilations. In: GC Denniston and MF Milos, eds. Sexual Mutilations: A Human Tragedy New York and London: Plenum Press, 1997 (ISBN 0-306-45589-7)
  38. Werker PMN, Terng ASC, Kon M. The prepuce free flap: dissection feasibility study and clinical application of a superthin new flap. Plastic & Reconstructive Surgery 1998;102(4):1075-82.
  39. Fleiss PM, Hodges FM, Van Howe RS. Immunological functions of the human prepuce. Sex Transm Inf 1998;74:364-7.
  40. Yang CC, Bradley WE. Neuroanatomy of the penile portion of the human dorsal nerve of the penis. Br J Urol 1998;82(1):109-13.
  41. Cold CJ, Taylor JR. The prepuce. BJU International 1999; 83, Suppl. 1: 34-44.
  42. O'Hara K, O'Hara J. The effect of male circumcision on the sexual enjoyment of the female partner. BJU Int 1999; 83, Suppl. 1:79-84.
  43. Cold CJ, McGrath KA. Anatomy and histology of the penile and clitoral prepuce in primates. In Male and Female Circumcision, Denniston GC, Hodges FM, Milos MF eds. Kluwer Academic/Plenum Publishers, New York, 1999.
  44. Taylor JR. Back and forth. Pediatrics News 2000;34(10):50.
  45. McGrath K. The frenular delta: a new preputial structure. In: Understanding Circumcision: A Multi-Disciplinary Approach to a Multi-Dimensional Problem. New York: Kluwer/Plenum, 2001; pp. 199-206.
  46. Taves D. The intromission function of the foreskin. Med Hypotheses 2002;59(2):180.
  47. Taylor JR. Letter. Can Fam Physician 2003;49:1592.
  48. Sorrells ML, Snyder JL, Reiss MD, et al. Fine-touch pressure thresholds in the adult penis. BJU Int 2007;99:864-9.

Other material

  1. Francisco Garcia. (1996) Some notes on the effects of circumcision including a discussion of "the triple whammy effect" to male sexuality.
  2. Some notes on the arterial/venous system of the pubic area and lower body (Martin Novoa):
  3. Some preliminary notes about various penile structures:

Anatomical Animated Graphics and Photographs

There is an animated anatomical drawing which graphically depicts in animation the deployment of Taylor's ridged bands by retraction of the prepuce. This is located off-site. (Link to www.circumstitions.com)

There is a collection of graphic close-up photographs of the adult prepuce which depict various anatomical features of the prepuce at another website. (Link to www.foreskin.org)

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