Mucocutaneous zone

A mucocutaneous zone is a region of skin comprising both mucosa and cutaneous skin. These mostly occur near the orifices of the body at which the external skin stops and the mucosa that covers the inside of the body starts.

A mucocutaneous zone is found at the lips, the conjunctival region, at the tip of the penis (notably the glans penis and ridged band), the vulva, the perianal zone, and similar locations.

Winkelmann reported the mucocutaneous boundary is a "specific erogenous zone with rete ridges where the nerve endings rise closer to the surface."