Infraorbital foramen

Where is the infraorbital foramen located?

The foramen is located on the anterior surface of the body of the maxilla (corpus maxillae), which has a concave shape.

• Topography: It is situated inferior to the infraorbital margin (margo infraorbitalis), which separates the anterior surface of the maxilla from its orbital surface.
• Canine fossa: Inferior to the foramen lies a bony depression known as the canine fossa (fossa canina).
• Relation to the orbit: The foramen is the anterior exit of the infraorbital canal (canalis infraorbitalis). The canal originates from the infraorbital groove (sulcus infraorbitalis) on the orbital surface; the infraorbital nerve passes through the inferior orbital fissure, the orbit, the infraorbital groove, and the infraorbital canal.

What structures pass through the infraorbital foramen?

The structures emerging through the foramen onto the face are:

• Infraorbital nerve (n. infraorbitalis), which is the direct continuation of the maxillary nerve. Upon exiting the foramen, it divides into its terminal branches; the superior labial branches form the minor goose's foot (pes anserinus minor).
• Infraorbital vessels — the infraorbital artery (a. infraorbitalis) and infraorbital vein (v. infraorbitalis).

Innervation zones

The terminal branches of the infraorbital nerve innervate:

• The skin and mucosa of the upper lip.
• The lower eyelid.
• The infraorbital region.
• The nasal alae.
• The skin of the nasal septum.

Note: The middle and anterior superior alveolar branches arise from the infraorbital nerve within the infraorbital canal and, together with the posterior superior alveolar nerves, form the superior dental plexus.

Clinical significance: Anesthesia

The infraorbital foramen serves as an anatomical landmark for extraoral infraorbital anesthesia (nerve block). Infraorbital anesthesia provides blockade of the anterior and middle superior alveolar nerves.

• Technique: The clinician determines the projection of the foramen onto the skin and fixes the tissues against the bone with a finger to prevent accidental injury to the eyeball and to facilitate locating the canal entrance. The needle is inserted 1 cm inferior and medial to the projection point. The needle is advanced superiorly, posteriorly, and laterally toward the infraorbital foramen until it contacts the bone. An anesthetic depot of 0.5–1 ml is deposited in the region of the foramen, after which the entrance to the canal is located. Indicators of correct entry include a "yielding" or dropping sensation of the needle or a pain response.
• Complications: Potential complications include vascular injury with hematoma formation, and ischemia of the skin in the infraorbital region. Rarely, if technique is improper, diplopia and infraorbital neuritis may occur.

Clinical significance: Surgery and traumatology

• Maxillary sinus surgery: During surgical approaches for odontogenic maxillary sinusitis, trephination of the anterior wall of the maxillary sinus is performed in the area of the canine fossa. When creating the surgical access, it is crucial not to injure the neurovascular bundle emerging from the infraorbital foramen to prevent hemorrhage and postoperative sensory disturbances.
• Facial trauma: In a Le Fort II midface fracture, the fracture line may run along the infraorbital canal and through the infraorbital foramen, resulting in damage to the infraorbital nerve.
• Neurology: Congenital or acquired narrowing of the canals at the exit sites of trigeminal nerve branches, including the infraorbital foramen, is among the etiological factors for peripheral neuralgia.

Class and exam questions

What else to study on this topic

• Maxilla (Maxilla)
• Infraorbital nerve (N. infraorbitalis)
• Maxillary nerve (N. maxillaris)
• Infraorbital anesthesia
• Canine fossa (Fossa canina)

Other topics in the "Anatomical Structures" section

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