_a_, Levator labii superioris proprius; _a′_, common tendon of a with opposite muscle; _b_, levator nasolabialis; _f_, dilatator naris lateralis; _g_, zygomaticus; _l_, dilatator naris superior; _n_, parotido-auricularis; _o″_, scutulo-auricularis superficialis superior; _p_, interscutularis; _p′_, fronto-scutularis, pars temporalis; _r_, cervico-auricularis superficialis; _u_, corrugator supercilii; _x_, transversus nasi; _2_, posterior, _3_, anterior, border of external ear; _8_, scutiform cartilage; _9_, zygomatic arch; _10_, supraorbital depression; _35_, inner wing of nostril, containing lamina of alar cartilage; _39_, facial vein. (After Ellenberger-Baum, Anat. für Künstler.) ] 3. =Levator labii superioris proprius.=—This lies on the dorso-lateral aspect of the face, partly covered by the preceding muscle. _Origin._—The lacrimal, malar, and maxillary bones at their junction. _Insertion._—The upper lip, by a common tendon, with its fellow. _Action._—Acting with its fellow, to elevate the upper lip. This action, if carried to the fullest extent, results in eversion. In unilateral action the lip is drawn upward and to the side of the muscle acting. _Structure._—The muscle has a short, thin tendon of origin. The belly is at first flattened, but becomes narrower and thicker, then tapers over the false nostril, to terminate in a tendon. The tendons of the two muscles unite over the alar cartilages of the nostrils, forming an expansion which spreads out in the substance of the upper lip. _Relations._—Superficially, the skin, the levator nasolabialis, and the angular vessels of the eye; deeply, the superior and transverse dilators of the nostril and the infraorbital artery and nerve. _Blood-supply._—Facial artery. _Nerve-supply._—Facial nerve. 4. =Zygomaticus.=—This very thin muscle lies immediately under the skin of the cheek. _Origin._—The fascia covering the masseter muscle below the facial crest. _Insertion._—The commissure of the lips, blending with the buccinator. _Action._—To retract and raise the angle of the mouth. _Structure._—Fleshy, with a thin aponeurotic origin. _Relations._—Superficially, the skin; deeply, the buccinator. _Blood-supply._—Facial artery. _Nerve-supply._—Facial nerve. 5. =Incisivus superior= (Depressor labii superioris).—This lies under the mucous membrane of the upper lip. _Origin._—The alveolar border of the premaxilla from the second incisor to the first cheek tooth. _Insertion._—The upper lip. _Action._—To depress the upper lip. 6. =Incisivus inferior.=—This is arranged in the lower lip like the preceding muscle in the upper one. _Origin._—The alveolar border of the mandible from the second incisor to a point near the first cheek tooth. _Insertion._—The skin of the lower lip and the prominence of the chin. _Action._—To raise the lower lip.