The Dilator naris muscle is a part of the nasalis muscle. It is divided into posterior and anterior parts. * The Dilator naris posterior is placed partly beneath the Quadratus labii superioris. It arises from the margin of the nasal notch of the maxilla, and from the lesser alar cartilages, and is inserted into the skin near the margin of the nostril. * The Dilator naris anterior is a delicate fasciculus, passing from the greater alar cartilage to the integument near the margin of the nostril; it is situated in front of the Dilatator naris posterior muscle.