Levator anguli oris muscle: anatomy
- Muscle
- Highlighted area
Quick facts
- Origin
- Canine fossa of the maxilla, just below the infraorbital foramen.
- Insertion
- Modiolus, at the mouth corner, blending with fibers of the orbicularis and the depressor anguli oris.
- Plane
- Deep to the levator labii superioris and the zygomaticus minor.
- Innervation
- Zygomatic and buccal branches of the facial nerve.
- Function
- Lifts the mouth corner and contributes to deepening the nasolabial fold in the smile.
The levator anguli oris, formerly called the caninus muscle, is a muscle of facial expression that lifts the mouth corner. It arises from the canine fossa of the maxilla, just below the infraorbital foramen, and runs down to the modiolus. It lies in a deeper plane than the other lip elevators, and the infraorbital vessels and nerve emerge between it and the levator labii superioris.
Where is the levator anguli oris?
| Point | Description |
|---|---|
| Origin | Canine fossa of the maxilla, below the infraorbital foramen |
| Course | Runs down obliquely, from above and inside to below and outside |
| Insertion | Modiolus, with fibers that blend with the orbicularis oris and the depressor anguli oris |
| Plane | Deep; covered by the levator labii superioris and the zygomaticus minor |
| Innervation | Zygomatic and buccal branches of the facial nerve |
The relative position of the elevators helps explain the midface in layers. More superficial and medial are the levator labii superioris alaeque nasi and the levator labii superioris; laterally, the zygomatics; and beneath them all, the levator anguli oris.
How does it relate to the infraorbital bundle?
The infraorbital nerve and the vessels of the same name leave the infraorbital foramen and fan out between the levator labii superioris, which is more superficial, and the levator anguli oris, which is deeper. This makes the muscle a plane landmark in the anatomy of the anterior cheekbone region and the base of the nose. The position of the foramen varies between people and between sides.
Why does it matter in facial harmonization?
- Smile: the muscle lifts the corner and takes part in the smile along with the zygomaticus major. Differences in strength between the sides show up in the height of the mouth corner.
- Nasolabial fold: contraction deepens the smile lines, which explains why the fold looks more marked in the smile than at rest.
- Mouth corners: the balance between the elevators and the depressor anguli oris defines the position of the corner, a topic covered in mouth corner filler.
- Toxin in the midface: in treatments of the perinasal region, spread to the elevators can alter the smile. See botulinum toxin for gummy smile.
How does it show up in the assessment?
- Spontaneous smile: height of the corner on each side.
- Rest vs. smile in the nasolabial fold: how dynamic the fold is.
- Symmetry of the mouth corner in standardized photos.
Also called: caninus muscle, levator of the angle of the mouth, musculus levator anguli oris.
Frequently asked questions
Is the caninus muscle the same as the levator anguli oris?
Yes. Caninus is the old name for the levator anguli oris, given because it arises from the canine fossa of the maxilla, above the root of the canine tooth.
What is the function of the levator anguli oris?
It lifts the mouth corner, helping with the smile and with symmetry of the corner. When it contracts, it also deepens the nasolabial fold.