What is a foreskin?

The penis consists of several major parts, but one useful way of looking at it is to divide it into an erectile portion (the part that gets stiff) and a non-erectile portion (the part that does not). The foreskin is the non-erectile portion. A more conventional definition would be to describe it as the soft, sensitive double-fold of tissue which covers the lower half of the penis shaft, extends in a sleeve over the head (glans) and usually ends in a tapering nozzle or spout. The outer layer is tender skin, the inner layer a sensitive mucous membrane. There is no agreed anatomical definition about where the foreskin ends and the skin of the penis shaft begins, and hence no exact surgical definition of what circumcision is meant to remove. As a consequence, the amount of tissue cut off by the operation is highly variable (some doctors take more, some less), but a typical circumcision carried out in a western hospital will remove about 50 per cent of the surface tissue of the penis.

The foreskin is not just a flap of skin, but a complex web of mucous membrane, muscle fibres, blood vessels and nerves: in fact, it supports one of the densest concentrations of nerves in the whole body. The underside of the penis (just beneath the glans) is called the fraenum, and this carries ridged bands which are densely packed with fine-touch nerve receptors and a very rich blood supply. The main nerve supplying the penis goes down to the end and then doubles back, allowing the foreskin to slide backwards and forwards, and showing that this is exactly what it evolved to be able to do. To operate at its best, the penis is meant to be covered with a mobile sheath of responsive flesh. - Dr. Robert Darby