Levator Anguli Oris
Facial Expression · Head & Neck
The levator anguli oris is a muscle of facial expression that lifts the corner of the mouth in smiling. It lies deep to the other lip elevators, arising from the canine fossa of the maxilla just below the infraorbital foramen, and its fibres descend to insert into the modiolus, the fibromuscular knot at the angle of the mouth where several facial muscles interlace. Contraction raises the angle of the mouth, contributing to the expression of smiling and helping to display the nasolabial fold. As a muscle of facial expression it is supplied by the facial nerve (CN VII), through its buccal and zygomatic branches. Its deep position beneath the infraorbital region means the infraorbital nerve and vessels emerge just above its origin.
Origin, Insertion, Action & Nerve
Origin
Canine fossa of the maxilla, below the infraorbital foramen
Insertion
Modiolus at the angle of the mouth
Action
Elevates the angle of the mouth (smiling)
Nerve
Buccal and zygomatic branches of facial nerve (CN VII)
Attachments explained
The Levator Anguli Oris is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Canine fossa of the maxilla, below the infraorbital foramen
Insertion
Modiolus at the angle of the mouth
Action & function
When the Levator Anguli Oris contracts, it produces the following movement: Elevates the angle of the mouth (smiling).
As part of the Facial Expression group of the Head & Neck, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Levator Anguli Oris receives its nerve supply from the Buccal and zygomatic branches of facial nerve (CN VII).
Because a muscle can only contract when its nerve is intact, injury to the Buccal and zygomatic branches of facial nerve can weaken or paralyse the Levator Anguli Oris, impairing the movements it normally produces (elevates the angle of the mouth (smiling)). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Levator Anguli Oris (the OIANS method)
Learn the levator anguli oris by its name and its target: it is a levator that raises the angle of the mouth, and it does so by pulling on the modiolus at the mouth's corner. Remember that it is the deepest of the muscles that converge on the modiolus, lying beneath levator labii superioris and zygomaticus, which explains why it is less visible but still a key smiling muscle.
Use its origin in the canine fossa, just below the infraorbital foramen, as a landmark that links it to the infraorbital nerve emerging above. Keep its innervation with the rest of the smiling muscles, the facial nerve (CN VII) through the buccal and zygomatic branches, and pair it mentally with its direct antagonist, the depressor anguli oris, which lowers the same corner of the mouth.
Frequently asked questions
Where is the Levator Anguli Oris located?
The Levator Anguli Oris is a muscle of the Facial Expression group, located in the Head & Neck.
What is the origin of the Levator Anguli Oris?
Canine fossa of the maxilla, below the infraorbital foramen
What is the insertion of the Levator Anguli Oris?
Modiolus at the angle of the mouth
What movements does the Levator Anguli Oris produce?
Elevates the angle of the mouth (smiling)
What nerve supplies the Levator Anguli Oris?
Buccal and zygomatic branches of facial nerve (CN VII)
Is the Levator Anguli Oris free to study in OIANS?
The Levator Anguli Oris is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Head & Neck is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
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