The levator labii superioris alaeque nasi, also known as the levator labii superioris alaequae nasi, is a facial muscle located in the nose and upper lip region of the face. It extends from the frontal process of the maxilla (upper jaw) to the skin of the upper lip and the alar cartilage of the nose. The muscle elevates the upper lip and dilates the nostrils, especially during deep inspiration. The levator labii superioris alaeque nasi muscle also contributes to specific facial expressions, such as snarling or sneering. It is innervated by the zygomatic branch of the facial nerve (cranial nerve VII) and works in conjunction with other facial muscles to produce a range of facial expressions. Dysfunction or weakness of the levator labii superioris alaeque nasi muscle can lead to difficulties with speech, eating, and facial expressions, such as snarling or smiling.