The cheek constitutes the facial periphery, plays a key role in the maintenance of oral competence and mastication, is involved in the facial manifestation of human emotion, and supports neighboring primary structures. The most common causes of acquired cheek defects are tumors, burns, and trauma; while congenital abnormalities in cheek contour may be due to facial clefts, vascular anomalies, or facial wasting syndromes. The repair of these defects seeks to achieve aesthetic and functional ends that must be carefully considered by the reconstructive surgeon. Aesthetic unit principles The face can be divided into six regions, referred to as facial aesthetic units, with unique anatomic and aesthetic features. There are three central and three peripheral aesthetic units: eyelids, nose and lips; and forehead, cheek and chin, respectively. The aesthetic surface anatomy characteristics of the cheek have been described eloquently by Menick: "The face can be divided into adjacent topographic areas of characteristic skin quality (color, texture, hair bearing), outline, and contour that define its regional units. The skin quality of the cheek matches the face in color and texture. The peripheral outline of the cheek unit is formed by the contours of the bordering units (forehead, eyelids, nose, lips, neck, and ear). Its outline follows the pre-auricular contours of the tragus and helix; goes around the sideburn, across the zygomatic arch, and into the lower eyelid-cheek junction; and then passes inferiorly along the nasal sidewall into the nasolabial fold and marionette line, around the chin and toward the submental crease. It then extends laterally along the jawline, passing superiorly up the angle of the jaw and back to the ear. In contour, the cheek is a relatively flat, expensive surface, except for the soft roundness of the nasolabial folds and cheek prominences." Surgical anatomy Vascular supply The external carotid artery (ECA), with contributions from the internal carotid artery (ICA) system, is the predominant arterial blood supply to the skin and muscles of the cheek. The greatest contribution is from the facial artery which traverses the face obliquely and terminates in the angular artery. The dorsal nasal artery runs along the nose and is the terminal branch of the ophthalmic artery, which is a terminal branch of the ICA. Many smaller branches and communications also exist. The venous drainage system of the cheek is predominantly formed by the anterior facial vein, which subsequently communicates with the internal jugular vein. However, substantial drainage