Philtrum
The vertical groove between the base of the nose and the top of the upper lip.
Also: medial cleft
The philtrum is the shallow channel in the middle of the upper lip, edged by two ridges called the philtral columns. It forms in the embryo where tissue growing from either side of the face joins in the middle. Its depth and length vary from person to person. It has no known use in adults, though it gives the upper lip flexibility. Folklore in several cultures tells stories about it, including one in which an angel touches each baby there.