Levator anguli oris muscle
Levator anguli oris is a paired strap-like muscle of the face, located above the angles of the lips. It belongs to a large group of muscles of facial expression called the buccolabial group. Besides levator anguli oris, this group also contains levator labii superioris alaeque nasi, levator labii superioris, zygomaticus major, zygomaticus minor, risorius, depressor labii inferioris, depressor anguli oris, mentalis, orbicularis oris, incisivus superior and inferior, and buccinator muscles.
Like all the buccolabial muscles, levator anguli oris’ function contributes to producing facial expressions by controlling the shape, position and movements of the lips. Specifically, it does so by elevating the angle of the mouth and deepening the nasolabial lines, facilitating smiling.
|Origin||Canine fossa of maxilla|
|Action||Elevates angle of mouth|
|Innervation||Zygomatic and buccal branches of facial nerve (CN VII)|
|Blood supply||Superior labial branch of facial artery, infraorbital branch of maxillary artery|
This article will discuss the anatomy and function of levator anguli oris muscle.
Origin and insertion
Levator anguli oris originates from the canine fossa of maxilla, inferior to the infraorbital foramen. After a short inferior course, it blends with the modiolus at the angle of the lips.
Modiolus is a fibromuscular nodule at the angle of the mouth formed by at least nine muscles. It serves as an attachment hub for most of the buccolabial muscles, thus integrating the movements of the lips with those of the jaw and cheeks. It’s exact characterization varies across different textbooks but it’s sure that the direct tractors of the lips contribute to modiolus; zygomaticus major, depressor anguli oris and orbicularis oris.
Levator anguli oris lies deep, and lateral, to levator labii superioris. These two muscles bound the infraorbital tissue space (canine space), which is clinically significant as odontogenic infections may spread into it. Infraorbital nerve and vessels pass between the bony attachments of levator anguli oris and levator labii superioris on their way to the face.
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Zygomatic and buccal branches of facial nerve (CN VII) innervate the levator anguli oris muscle.
Levator anguli oris elevates the angle of lips, which deepens the nasolabial folds and enables smiling.