Foreskin
The foreskin or prepuce is a retractable double-layered fold of skin and mucous membrane that covers the
glans penis and protects the urinary meatus when the penis is not erect. Almost all mammals have foreskins, although in these non-human cases the foreskin is usually a sheath into which the whole penis is retracted. Only
monotremes lack foreskins.
Encyclopedia
The
foreskin or
prepuce is a retractable double-layered fold of skin and mucous membrane that covers the
glans penis and protects the urinary meatus when the penis is not erect. Almost all mammals have foreskins, although in these non-human cases the foreskin is usually a sheath into which the whole penis is retracted. Only
monotremes lack foreskins.
The human foreskin
Description
In humans, the outside of the foreskin is like the skin on the shaft of the penis but the inner foreskin is a mucous membrane like the inside of the eyelid or the mouth. Like the eyelid, the foreskin is free to move. Smooth muscle fibres keep it close to the glans but make it highly elastic. At the end of foreskin there is a band of tissue called the ridged band which, according to one study, is rich in nerve endings called Meissner's corpuscles The foreskin is attached to the glans with a
frenulum which helps retract the foreskin over the glans.
In children, the foreskin covers the glans completely but in adults this need not be so. In a German study, found that about 50% of young men had full coverage of the glans, 42% had partial coverage, and in the remaining 8%, the glans was uncovered. After adjusting for
circumcision, he stated that in 4% of the young men the foreskin had spontaneously atrophied .
Development
Eight weeks after fertilization, the foreskin begins to grow over the head of the penis, covering it completely by 16 weeks. At this stage the foreskin and glans share an epithilium that fuses the two together. It remains this way until the foreskin separates from the glans.
At birth, the foreskin is usually still fused with the glans. As childhood progresses the foreskin and the glans gradually separate, a process that may not be complete until the age of 17. A Danish survey reported that average age of first foreskin retraction in Denmark is 10.4 years. Wright argues that forcible retraction of the foreskin should be avoided and that the child himself should be the first one to retract his own foreskin Premature retraction may be painful, and may result in infection.
Functions
In koalas the foreskin contains naturally occurring bacteria that play an important role in fertilization. Some also believe that the foreskin has protective and erogenous functions in humans, though this is disputed. Cold and Tayor stated "The prepuce is primary, erogenous tissue necessary for normal sexual function." Shen found a statistically significant * increase in erectile dysfunction following circumcision. Pang and Kim reported
"Of those who were circumcised long after they had been sexually active, > 80% reported no noticeable difference in sexuality, but a man was twice as likely to have experienced diminished sexuality than improved sexuality." Fink's study of American men also found significantly worsened erectile function * Other studies came to different conclusions. Collins , Senkul , and Masood found no significant difference in erectile function. Senkul found that the circumcised men took significantly longer to ejaculate after circumcision *.
Denniston states that the foreskin's innervation provides input to the central and autonomic nervous system to provide erectile function, stimulate ejaculation, and provide pleasure. Fink's study reported less sensitivity after circumcision, though this only bordered on statistical significance *. though their theory has been challenged. Inferior hygiene has been associated with balanitis, though excessive washing can cause non-specific dermatatis.
Conditions
Frenulum breve is where the frenulum is insufficiently long to allow the foreskin to fully retract, which may lead to discomfort during intercourse. The frenulum may also tear during intercourse.
Phimosis is a condition when the foreskin of an adult cannot be retracted properly. Phimosis can be treated by gently stretching the foreskin, by changing masturbation habits, using topical
steroid ointments,
preputioplasty, or by
circumcision. See phimosis for more information.
A condition called paraphimosis may occur if a tight foreskin becomes trapped behind the glans and swells as a restrictive ring. This can cut off the blood supply, resulting in ischaemia of the glans penis.
Aposthia is a rare condition in which the foreskin is not present at birth.
Surgical and other modifications of the foreskin
Circumcision is the removal of the foreskin, either partially or completely. It may be done for religious, aesthetic, health, or hygiene reasons, or to treat disease.
Preputioplasty is a procedure to relieve a tight foreskin without resorting to circumcision.
Other practices include genital piercings involving the foreskin and slitting the foreskin.
Research use
The foreskin, being the part of the male anatomy removed by circumcision, is frequently used by biochemical and micro-anatomical researchers to study the structure and proteins of human skin.
Langerhans cells
The inner surface of the foreskin, especially the downpart, contains Langerhans' cells with
HIV receptors; these cells are likely to be the primary point of viral entry.
See also
References
External links
-
- Lakshmanan S., Prakash S. . Indian J Surg 1980;44:134-7.
- Davenport M. . British Medical Journal 1996;312:299-301.
- Simpson ET, Barraclough P. . Aust Fam Physician 1998;27:381-3.
- Cold CJ, McGrath KA. . Male and Female Circumcision 1999
- Video "The Prepuce" a film prepared by Doctors Opposing Circumcision for medical students.
http://www.doctorsopposingcircumcision.org/DOC/prepuce.html
http://www.doctorsopposingcircumcision.org/video/Circumcision_WM7NTSC_256k_D.wmv
