Levator Labii Superioris

Description

Centered on the anterior midface, the levator labii superioris is traced as it descends from the inferior orbital margin of the maxilla to the upper lip, lying superficial to the maxillary bone and deep to the skin of the nasolabial region. Medial to it sit the lateral nasal cartilages and the sidewall of the nasal aperture, while laterally it approaches the zygomaticus minor and the zygomatic body. The infraorbital foramen occupies a superior and slightly lateral position relative to the muscle belly, with the infraorbital neurovascular bundle expected to emerge deep to the muscle before fanning toward the upper lip and cheek. Bony landmarks including the nasal bone, maxilla, zygoma, mandible with dentition, and the cervical vertebrae frame the field. A clean set of reference points. Surgeons and anesthetists care about this relationship because the levator labii superioris can obscure the infraorbital foramen during dissection and during infraorbital nerve blocks, and needle placement too medial risks the nasal sidewall while too inferior drifts toward the canine fossa. Weakness of this muscle contributes to upper-lip ptosis and flattening of the nasolabial fold in facial nerve palsy, and it becomes a structure to identify and preserve during midface approaches such as sublabial access for orbital floor fracture repair or during scar revision around the nasolabial crease. The muscle also helps explain why infraorbital nerve injury produces paresthesia of the upper lip and lateral nose. Course directors can drop this figure directly into head and neck anatomy modules, facial expression laboratories, or dental anesthesia teaching on infraorbital infiltration, and publishers will find it fits well in chapters on the mimetic musculature, facial nerve branches, and midface surgical landmarks. Anatomical accuracy verified by SciePro's Medical Advisory Board.