The foreskin is a continuation of the skin of the penis shaft which forms a fold over the glans of the penis. Shown to the right are three views labelling the various parts of the foreskin and shaft skin. Since it is a fold, the inner foreskin (in green) and the outer foreskin (in turquoise) are continuous with each other, and also freely mobile with respect to each other.

The frenulum is a web of skin that helps the foreskin to retract during erection and return when flaccid. After circumcisison it is redundant - it may be retained or removed during circumcision. In the illustration to the left, the foreskin has been pulled back and the frenulum is highlighted in yellow. Likewise, the amount of inner and outer foreskin that is retained or removed is up to you and your physician.