The Probert Encyclopaedia of Medicine

LEVATOR ANGULI ORIS

The levator anguli oris (triangularis labii superioris) muscle originates immediately below the maxillary foramen and extends inward and downward and is inserted in the skin at the angle of the mouth near the orbicularis oris muscle. It is innervated by the facial nerve (VII cranial nerve) and is supplied by the facial artery. This muscle raises the angle of the mouth and is one of the muscles used when smiling.
Research Levator Anguli Oris