ABSTRACT
The glabrous skin of the upper lip extends from the lower end of the nose to the vermilion zone that is the transitional zone between the skin and the mucous membrane. Under the skin of the external surface, which contains many pilosebaceous structures, there are bundles of striated muscle, particularly the orbicularis oris muscle, circumoral muscles intimately associated with the orbicularis oris, the submucosal layer, and on the inner surface the mucous membrane with many minor salivary glands. The upper lip includes the philtrum, a midline depression, also known as Cupid’s bow, extending from the columella of the nose to the superior edge of the vermilion zone, and laterally is bordered by the nasolabial fold. The commissures are the angles of the mouth where both lips, upper and lower, are jointed (1).
