levator anguli oris

Specifically, the levator anguli oris is innervated by the buccal branches of the facial nerve.

The levator anguli oris (caninus) is a facial muscle of the mouth arising from the canine fossa, immediately below the infraorbital foramen.

It is located between the levator anguli oris muscle inferiorly and the levator labii superioris muscle superiorly.

This occurs when pus (e.g. from a periapical abscess), perforates the buccal cortical plate of the maxilla above the level of attachment of the levator anguli oris muscle.

It is contributed to by the following muscles: orbicularis oris, buccinator, levator anguli oris, depressor anguli oris, zygomaticus major, risorius, platysma, levator labii superioris.

A dissection in the deep plane can mostly be performed safely, because the facial nerve innervates the facial muscles on the deep surface of these muscles (except for the muscles which are lying deep to the facial nerve, the mental nerve, the levator anguli oris and the buccinator).