The levator anguli oris lifts the corner of the mouth upward and slightly medially, deepening the nasolabial fold and contributing to the smile expression. It lies deep to the zygomaticus major and levator labii superioris, forming the deeper layer of the smile muscle complex. Along with the zygomaticus major it constitutes the primary smile mechanism and is targeted in facial reanimation procedures.
| Origin | Canine fossa of the maxilla below the infraorbital foramen |
|---|---|
| Insertion | Modiolus at the angle of the mouth |
| Nerve Supply | Buccal branch of the facial nerve (CN VII) |
| Blood Supply | Infraorbital artery |
| Actions | Elevates the oral commissure; Deepens the nasolabial fold; Assists in producing a happy or determined expression |
|---|
Its upward-medial pull differs from the zygomaticus major's upward-lateral pull, together producing the full smile shape of upturned and outwardly extended oral commissure.
The levator anguli oris is identified during cheek dissection in facelift surgery as the deepest component of the perioral smile complex. Its weakness contributes to the asymmetric, forced appearance of smiles in patients with incomplete facial nerve recovery after Bell palsy.
Not directly palpable as it lies deep to the zygomaticus major and levator labii superioris in the cheek.
Levator anguli oris weakness in facial nerve recovery producing an asymmetric oral commissure position at rest and during smiling.
