The levator labii superioris is a thin, wide, quadrilateral-shaped facial muscle of the oral group responsible for lifting the upper lip. It originates from the infraorbital margin and travels inferomedially toward the upper lip.

It is laterally bordered by the zygomaticus minor muscle and medially by the levator labii superioris alaeque nasi. Beneath it lies the levator anguli oris.

Origin and insertion of levator labii superioris

This muscle ends by inserting into the skin and muscular substance of the mid-lateral portion of the upper lip. It blends with the muscles forming the upper lip mass (mainly the orbicularis oris muscle). The levator labii superioris inserts between the lateral extension of the levator labii superioris alaeque nasi and zygomaticus minor.

Functionally, this muscle works together with other muscles to elevate and evert the upper lip, contributing to facial expressions such as smiling, disdain, or disgust. It also helps expose the maxillary teeth.

Origin: infraorbital margin of the maxilla, just above the infraorbital foramen.

Insertion: skin of the mid-lateral portion of the upper lip, between the lateral extensions of the levator labii superioris alaeque nasi and zygomaticus minor; blends with the upper lip muscles.

Action: elevates and everts the upper lip.

Innervation: buccal and zygomatic branches of the facial nerve (CN VII).

Arterial blood supply: angular and superior labial arteries of the facial artery and the infraorbital artery of the maxillary artery.

Venous drainage: tributaries of the facial vein and infraorbital vein, which drains into the pterygoid venous plexus.

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Levator labii superioris