Infraorbital nerve

Structure

Origin

The infraorbital nerve is a branch of the maxillary nerve (CN V₂), itself a branch of the trigeminal nerve (CN V); it may be considered as the terminal branch of the maxillary nerve. It arises from the maxillary nerve in the pterygopalatine fossa.

Course

It travels through the inferior orbital fissure to enter the orbit. It runs anteriorly along the floor of the orbit in the infraorbital groove to the infraorbital canal of the maxilla. Within the infraorbital canal it has three branches, the posterior superior alveolar nerve, middle superior alveolar nerve and anterior superior alveolar nerve. After traversing the canal it emerges onto the anterior surface of the maxilla through the infraorbital foramen. Here, it divides into its terminal branches; palpebral, nasal and superior labial.

Branches

Within infraorbital canal from proximal to distal:

• posterior superior alveolar nerve.
• middle superior alveolar nerve.
• anterior superior alveolar nerve.

After it exits the infraorbital foramen:

• palpebral branches.
• nasal branches.
• superior labial branches.

The palpebral branches ascend deep to the orbicularis oculi and pierce the muscle to supply the skin of the lower eyelid. The nasal branches supply the skin of the side of the nose and the moveable part of the nasal septum. The superior labial branches descend deep to the levator labii superioris to supply the skin of the anterior cheek and upper lip.

Relations

Along its course, the infraorbital nerve is accompanied by the infraorbital artery and vein.

Distribution

The infraorbital nerve provides sensory innervation to the skin of the lower eyelid, the side of the nose, the moveable part of nasal septum, the anterior cheek, and part of the upper lip. It does not provide motor supply to any muscles.