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1857: The reflex action of the foreskin |
Sir James Paget foreshadows modern researchIn recent times there has been a considerable effort to retrieve and restore the traditional knowledge about the importance of the foreskin for male sexual function (and female sexual enjoyment) that was common before the rise of the masturbation phobia and the consequent establishment of circumcision as a valid medical intervention. While several studies have shown that the presence of the foreskin makes a significant contribution to male sexual sensation, the Canadian pathologist John Taylor has gone further to suggest that the foreskin also plays an important role in the reflex actions that govern both erection and ejaculation. On these points, it is interesting to find that his hypotheses were anticipated by the prominent nineteenth century physiologist, James Paget, who recognised the role of the prepuce in reflex actions as early as the 1850s. Whether Paget's comments were ever published in a medical journal or in one of his own publications must await further research, but we do have a letter that he sent to William Acton, published in the first and second editions (1857 and 1858) of his best-selling treatise, The Functions and Disorders of the Reproductive Organs. Acton dropped Paget's comments from all subsequent editions of this book, and the reason is not far to seek. The decision had nothing to do with the scientific validity of Paget's suggestions, but was determined because Acton wanted to promote circumcision – as an aid to chastity, a preventive of masturbation, and a protection against syphilis – and was well aware any evidence as to the physiological significance of the foreskin had to be suppressed. If people were aware that the foreskin made a difference to male sexual response, it would be much harder to convince them to cut it off. Although Acton wanted to assert that there is no difference in sexual sensation between the normal and the circumcised penis, he was at least honest enough to admit that the question is difficult, if not impossible, to answer. The same degree of honesty is not, sadly, apparent in some of his anti-foreskin disciples today. The relevant passages from Functions and Disorders of the Reproductive Organs (2nd edition, 1858) are reproduced below. Sexual congress, or the act of copulationIn order to fulfil the purposes of the Creator, sexual congress is necessary. This is brought about by the influence of the sex-passion; and for its more certain fulfilment is attended with a considerable degree of pleasure. Mr Paget thinks that the prepuce is of importance in exciting the reflex action. He has kindly committed his opinion to paper. He says —"The function of the prepuce in the act of copulation is explicable on the principle that, other things being equal, the force of a reflex act is directly proportionate to the force of the incident impression which it follows. The contraction of the pupil is thus a measure of the intensity of light on the retina: the quantity and rapidity of secretion of saliva is proportionate to the quantity and strength of an irritant taken into the mouth; and so on, in numerous instances. "In like manner, the energy of the secretion and expulsion of the seminal fluid during copulation will (other things being equal) be proportionate to the quantity of highly excitable surface which is stimulated by the act. The mucous membrane of the prepuce, naturally reverted during copulation, supplies a large extent of highly-excitable surface; and the stimulus of its nerves, added to that of the nerves of the glans, increases the force of the incident impression on the spinal cord (and brain), and thus increases, in the same measure, the force of all the reflex acts. The importance of the prepuce, in this view, may be estimated by the difference between the sensibility of its mucous membrane and that of the common integument of the penis, or that of such a scar as may remain after circumcision." [The preceding passage is found only in the 1st and 2nd editions, 1857 and 1858; it was removed from all subsequent editions. The following paragraphs were substantially retained in subsequent editions, but heavily revised. Acton's following comments explain why.] Admitting, as I do, that this distinguished physiologist is right in the abstract, I still am of opinion that the prepuce in man (at least in civilized life) is the cause of much mischief, and that we could well spare that organ. As affording an additional surface for the excitement of the reflex action, this fold of membrane, in the present state of society, aggravates an instinct rather than supplies a want. The tenor of all I daily observe shows that, in the unmarried, it additionally excites the sexual desires, which it is our object to repress. In the act of sexual congress its existence may, I grant, give additional pleasure; and as age advances it may be necessary to copulation. Without it there may be a difficulty in exciting the flagging powers; but in the present state of society, all tends to prove that we require restraint, not excitement. In animals, the prepuce, I admit, not only protects the delicate glans penis from injury, but enables the intromittent organ of the male to be brought into an erect state by yielding to an extent that is not required in the human being. ... In monkeys there is no fraenum, [1] and this, doubtless, serves some good purpose, although we may fail to discover it. Man, in a state of nature, and the lower classes of civilized society, receive thorough protection from the foreskin; but to the sensitive, excitable, civilized individual the prepuce often becomes an additional source of mischief. In the East, the collection of the secretions between it and the glans causes irritation and its consequences; hence the origin of circumcision. That the existence of the foreskin predisposes to many forms of syphilis, no one can doubt; and, lastly, I am fully convinced that the excessive sensibility induced by a narrow foreskin, and the difficulty of withdrawing it, is often the cause of emissions, masturbation, or undue excitement of the sexual desires, which it becomes very difficult for the sufferer to endure. That Jews and those who have undergone circumcision enjoy as much pleasure in the copulative act as the uncircumcised admits of no decisive proof; but I am assured by those well able to speak upon the subject, that the former do not complain. Source: William Acton, The Functions and Disorders of the Reproductive Organs in Youth, in Adult Age and in Advanced Life. Considered in their Physiological, Social and Psychological Relations, 2nd edn (London: John Churchill, 1858), pages 23-24 Note1. In fact, chimpanzees, the closest relative to humans, have a foreskin but no glans, suggesting that the former is the more important structure. It is conventionally assumed that the key element of the penis is the glans and often said that the main function of the foreskin is to "protect it", but the fact that the only penile features common to all primates are the prepuce and corpus cavernosum suggests the plausibility of John Taylor's contrary suggestion that the glans may well be there to protect and support the foreskin. See Cold and Taylor, "The prepuce", 1999; Chris Cold and Ken McGrath, "Anatomy and histology of the penile and clitoral prepuce in primates: Evolutionary perspective of specialised sensory tissue in the external genitalia", in George C. Denniston, Frederick Hodges and Marilyn Milos (eds), Male and female circumcision: Medical, legal and ethical considerations in pediatric practice (New York: Kluwer Academic/Plenum Publishers, 1999), p. 23; and Taylor et al, The Prepuce, 1996.John Taylor on the importance of the ridged bandTaylor criticises studies of "penis sensitivity" that concentrate on the glans or shaft and forget the foreskin and its ridged band – the very structure that both carries the nerves and provides the mobility that stimulates the other regions of the organ.The following letter was published in BJU International. Fine-touch pressure thresholds in the adult penisVan Howe et al. [1] found that the prepuce, particularly its ridged band [2,3] is the part of the penis (including the glans) most sensitive to fine touch. This finding is important because it has always been assumed, for good reason, that the glans is by far the most sensitive and important part of the penis. Early and inadequate laboratory studies [1] propelled the idea that 'sex is sex is sex', regardless of circumcision status. Suddenly, the prepuce could be sacrificed with a clear conscience and with no sexual consequences. The anatomy and physiology of the prepuce show otherwise.The range of functions of the ridged band remains uncertain but it is deeply corrugated, rich in distortion-sensitive Meissner corpuscles and subject to the movement of muscularised shaft skin during sexual intercourse. It now seems that the concertina-like ridged band might be reflexogenic as much as fine-touch sensitive. Initial study (J.R.T. unpublished) indicates that the real importance of the ridged band to sexual intercourse lies in an ability to trigger a reflex contraction of muscles responsible for ejaculation. Routine infant circumcision is under attack in Canada and the USA, but we need to know much more about the function of the prepuce in sexual intercourse. Van Howe and his team have contributed to this ideal, and at the same time opened the hide-bound debate on circumcision to fresh thinking. John R. Taylor Department of Pathology, University of Manitoba, Winnipeg, Manitoba, Canada References 1. Sorrells ML, Snyder JL. Reiss MD et al. Fine-touch pressure thresholds in the adult penis. BJU Int 2007; 99 : 864–9 2. Taylor JR, Lockwood AP, Taylor AJ. The prepuce: specialized mucosa of the penis and its loss to circumcision. Br J Urol 1996; 77 : 291–5 3. Cold CJ, Taylor JR. The prepuce. Temp. BJU Int 1999; 83 (Suppl. 1):34–44 Source: BJU Int 2007;100(1):218. The forgotten foreskin and its ridged bandAnd similarly in this letter to the Journal of Sexual Medicine.Circumcision does not diminish the sensitivity of the glans and penile shaft skin [1]. However, the prepuce is always front and center in the great circumcision debate and direct comparison of the glans with prepuce, not shaft skin, is essential. The glans is naturally insensitive to fine touch whether the penis is circumcised or not [2], and study of the effect of circumcision on sexual function should therefore focus on the missing prepuce. Biologically, however, both glans and prepuce contribute to the single mucocutaneous junctional zone of the penis, and it is possible that these apparently dissimilar structures in fact share similar functions related more to sexual reflexes than to touch perception. The ridged band of prepuce [3,4] is tucked just inside the tip of the unretracted prepuce; it is a richly vascular mucosal tissue heavily innervated by movement-sensitive Meissner corpuscles. In addition to touch sensitivity [2], the ridged band is uniquely ridged or corrugated, and not surprisingly, work in progress indicates that retraction and stretching of this accordion-like structure triggers reflex contraction of bulbocavernosus and bulbospongiosus. These "bulb muscles" compress the root or bulb of the penis and among other things, including deep erogenous sensation, are responsible for ejaculation and clearing of residual urine from the posterior urethra following micturition. Almost certainly, removal of the prepuce and its ridged band distorts penile reflexogenic functions but exactly how and to what extent still remains to be seen. John R. Taylor Winnipeg, Manitoba, Canada References 1. Payne K, Thaler L, Kukkonen T, Carrier S, Binik Y. Sensation and sexual arousal in circumcised and uncircumcised men. J Sex Med 2007;4:667–74. 2. Sorrells ML, Snyder JL, Reiss CE, Milos MF, Wilcox N, Van Howe RS. Fine-touch pressure thresholds in the adult penis. BJU Int 2007;99:864–9. 3. Taylor JR, Lockwood AP, Taylor AJ. The prepuce: Specialized mucosa of the penis and its loss to circumcision. Br J Urol 1996;77:291–5. 4. Cold CJ, Taylor JR. The prepuce. BJU Int 1999;83 (1 suppl):34–44. Source: J Sex Med 2007;4:1516 Further information on John Taylor's website: The ridged band. |