Corpus: Levator anguli oris muscle

The levator anguli oris muscle is part of the deeper layer of facial muscles responsible for expressions around the mouth. Its primary function is to lift the corner of the mouth.

The levator anguli oris muscle originates from the canine fossa of the maxilla, just below the infraorbital foramen. Its fibers run downward and laterally to the corner of the mouth, where they insert. At this point, the muscle fibers merge with those of the zygomaticus major, depressor anguli oris, and orbicularis oris muscles at the modiolus anguli oris.

The outward-facing surface of the levator anguli oris muscle is covered by the levator labii superioris alaeque nasi muscle and is crossed by the zygomatic muscles as well as the infraorbital vessels and nerves. The inward-facing surface is adjacent to the maxilla, the buccinator muscle, and the oral mucosa.

The levator anguli oris muscle is innervated by the buccal branches of the facial nerve (cranial nerve VII).

The primary function of the levator anguli oris muscle is to lift the corner of the mouth. It also plays a role in smiling, working in conjunction with the risorius muscle.