The levator labii superioris elevates the upper lip and deepens the nasolabial fold, contributing to expressions of disgust, sadness, and sneering. It works with the zygomaticus minor and levator labii superioris alaeque nasi in elevating the lip. The infraorbital nerve exits the maxilla just below its origin, making infraorbital nerve injury from fractures or surgical approaches produce altered upper lip sensation.
| Origin | Infraorbital margin of the maxilla and zygomatic bone |
|---|---|
| Insertion | Upper lip skin and muscle, lateral part of the philtrum |
| Nerve Supply | Zygomatic and buccal branches of the facial nerve (CN VII) |
| Blood Supply | Infraorbital artery; Superior labial artery |
| Actions | Elevates the upper lip; Deepens the nasolabial fold |
|---|
Elevating the upper lip to expose the upper teeth, it contributes to both emotional expressions and the mechanical lip movement during speech for labial and labiodental consonant production.
Infraorbital nerve injury from zygomaticomaxillary fractures or periorbital surgery produces ipsilateral upper lip and cheek numbness that can persist for months. The levator labii superioris is a common target for Botulinum toxin injections to reduce a gummy smile (excessive upper lip elevation exposing gingival tissue above the upper teeth).
Palpable in the nasolabial region between the infraorbital rim and the upper lip, becoming firm during deliberate upper lip elevation.
Excessive upper lip elevation from hyperactive levator labii superioris exposing more than 3 mm of gingiva during smiling, managed with Botulinum toxin injection or surgical levator release.
