Functions of the Foreskin

Dr Peter Ball MB,B Chir

Last updated on 22nd June 2003

The foreskin has protective, sensory and sexual functions

Anatomy

The foreskin begins immediately behind the glans (the head of the penis) and comes forward to sheath the glans and then doubles back on itself to form an outer layer that joins the shaft skin behind the glans. How much of the glans is covered by the skin is very variable. Still more variable is the coverage remaining when the penis is erect. The inner lining has a very sensitive erogenous mucosa that becomes ridged and especially erogenous just inside the foreskin opening. The ridges sweep round the glans to be gathered up into the fleshy attachment to the underside of the glans called the frenulum (frenum or 'banjo string'). This varies considerably in length. If too short (frenulum breve), it severely limits how far the foreskin can be retracted and may be torn during the process. The frenulum for many is the most sexually sensitive part of the penis. It also guides the retracted foreskin back over the glans. If the frenulum is excised during a circumcision the area that it came from is often the most erogenous on the penis.

The foreskin represents 50% to 80% of the skin system of the penis depending on the length of the penile shaft. The average foreskin has over three feet of veins, arteries, and capillaries, 240 feet of nerve fibres, and over 20,000 nerve endings. Unfolded, the adult foreskin measures 10 to 15 square inches. This is roughly the area of a five-pound note.1

Anatomy: Further Reading at CIRP (external site with diagrams)

Anatomy: Further Reading - The Ridged Band (external site with pictures)

Erogenous Sensitivity

The foreskin is as sensitive as the fingertips or the lips of the mouth. It contains a richer variety and greater concentration of specialised nerve receptors than any other part of the penis. These specialised nerve endings can discern motion, subtle changes in temperature, and fine gradations of texture. They are concentrated along an area called the Ridged Band 2 which radiates from the frenulum and encircles the tip of the foreskin just within the junction between the outer and inner skin. It is stimulation of the Ridged Band that causes erogenous feelings in the foreskin.

Protective functions

Just as the eyelids protect the eyes, the foreskin protects the glans and keeps its surface soft, moist, and sensitive. It also maintains optimal warmth, pH balance and cleanliness. The foreskin is believed to produce sebum that maintains proper health of the surface of the glans.

Coverage during erection

As it becomes erect, the penile shaft becomes thicker and longer. The double-layered foreskin provides the skin necessary to accommodate the expanded organ and to allow the penile skin to glide freely, smoothly, and pleasurably over the shaft and glans. Coverage at erection ranges from nil to total. All these variations are normal.

Immunological functions

The mucous membranes that line all body orifices are the body's first line of immunological defence. Apocrine glands in the foreskin produce antibacterial and anti-viral proteins such as lysozyme, which is also found in mother's milk.

Sexual Functions in Intercourse

One of the foreskin's functions is to facilitate smooth gentle movements between the mucosal surfaces of the two partners by its rolling action along the shaft and over the glans during intercourse.

References

1 - Werker PMN, Terng ASC, Kon M. The Prepuce Free Flap: Dissection Feasibility Study and Clinical Application of a Super-Thin New Flap. Plast Reconstr Surg. 1998; 102:1075-1082.

2 - Taylor JR, Lockwood AP, Taylor AJ. The Prepuce: Specialized Mucosa of the Penis and its Loss to Circumcision. BJU Int. 1996; 77:291-295.