The Nasolabial fold ("nose-lip-furrow"; from lat. nasus "nose" and labium "lip") is a soft-tissue-deepening which exists that on both sides of the face between the corners of the mouth and the nasal ala. This brings a special characteristic to the the face. The shape, depth, and length of the nasolabial fold are determined by the facial muscles, the different extent of the subcutaneous fatty tissue present and the age.
Nasolabial folds are of major importance for symmetry. If they are missing on one side, as is often the case with flaccid facial paralysis, the result is a rather noticeable disturbance of the facial symmetry. An effaced nasolabial fold is completely missing. It can be restored by various plastic surgery techniques. Ideally, it can be restored "naturally" by introducing new muscles (muscle transplantation or muscle rearrangement) through the newly gained underlying muscle activity. If this is not possible, it can be reconstructed with precisely inserted static suspension procedures. Frequently, an additional incision is made in the skin using a special suturing technique.