In male human anatomy, the foreskin or prepuce (a technically broader term that also includes the clitoral hood) 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. It is embryonically homologous to the clitoral hood in women.

Description

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 after it separates from the glans, usually by puberty. Smooth muscle fibres keep it close to the glans but make it highly elastic. The foreskin is attached to the glans with a frenulum, which helps retract the foreskin over the glans. 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. According to a study by Sorrells et al., the five most sensitive areas of the penis are on the foreskin.

In children, the foreskin covers the glans completely, but, in adults, this need not be so. Schöberlein 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 (shrunk).

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 epithelium (mucous layer) 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 late puberty. Thorvaldsen and Meyhoff 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

The World Health Organization state that there is "debate about the role of the foreskin, with possible functions including keeping the glans moist, protecting the developing penis in utero, or to enhance sexual pleasure due to the presence of nerve receptors".

Sexual

detail: Sexual effects of circumcision

Taylor et al described the foreskin in detail, documenting a ridged band of mucosal tissue. They stated "This ridged band contains more Meissner's corpuscles than does the smooth mucosa and exhibits features of specialized sensory mucosa." In 1999, Cold and Taylor stated "The prepuce is primary, erogenous tissue necessary for normal sexual function." Boyle et al, state that "The complex innervation of the foreskin and frenulum has been well-documented, and the genitally intact male has thousands of fine touch receptors and other highly erogenous nerve endings—many of which are lost to circumcision, with an inevitable reduction in sexual sensation experienced by circumcised males." The AAP noted that the work of Taylor et al "suggests that there may be a concentration of specialized sensory cells in specific ridged areas of the foreskin."