Infraorbital canal

Location and structure

The canal lies within the body of the maxilla (corpus maxillae).

It begins on the orbital surface (facies orbitalis), which contributes to the formation of the floor of the orbit. Here, the infraorbital groove (sulcus infraorbitalis) is located, continuing into the infraorbital canal.

The exit of the canal is located on the anterior surface of the maxilla (facies anterior) and is called the infraorbital foramen (foramen infraorbitale). It is situated inferior to the infraorbital margin (margo infraorbitalis) and opens into a depression known as the canine fossa (fossa canina).

The axis of the anterior segment of the canal is directed forward, medially, and downward. The axes of the right and left canals intersect slightly superior to the incisive papilla between the upper central incisors.

What passes through the infraorbital canal?

Inside the canal lies the infraorbital neurovascular bundle, which emerges into the loose adipose tissue of the canine fossa:

• Infraorbital nerve (n. infraorbitalis) is the terminal branch of the maxillary nerve, the second division of the trigeminal nerve. It gives off the anterior and middle superior alveolar branches. After exiting the foramen, the nerve forms the lesser goose's foot (pes anserinus minor). The area of sensory innervation includes the skin of the infraorbital region, upper lip, lateral surface of the nose, and lower eyelid.
• Infraorbital artery (a. infraorbitalis) is a branch of the third, pterygopalatine part of the maxillary artery. Within the canal, it gives off the anterior superior alveolar arteries (aa. alveolares superiores anteriores).
• Infraorbital vein — drains into the inferior ophthalmic vein or the pterygoid venous plexus.

Topography and anatomical connections

Through the infraorbital canal, the orbit communicates with the facial region, the maxillary sinus, and the dental alveoli of the incisors and canines.

The adipose tissue of the infraorbital region communicates with the orbital fat through the infraorbital canal.

Clinical significance

• Infraorbital nerve block: used for anesthesia of the incisors, canine, premolars, and partially the medial buccal root of the first molar, as well as the adjacent bone and soft tissues on the vestibular side. In the extraoral technique, the needle is directed posteriorly, laterally, and superiorly — opposite to the axis of the canal. Modern methodology involves depositing the anesthetic solution at the entrance to the infraorbital canal without introducing the needle into the canal itself, which reduces trauma during anesthesia. Potential complications include vascular injury, hematoma, skin ischemia, diplopia, and infraorbital neuritis.
• Path of infection spread: the adipose tissue of the infraorbital region communicates with the orbit via the infraorbital canal. In odontogenic infections, the sources can be the upper incisors, canines, and premolars. In thrombophlebitis of the angular vein of the face, the orbital veins, which drain directly into the cranial venous sinuses, can become involved. This may lead to cavernous sinus thrombosis, meningitis, and meningoencephalitis.
• Trigeminal neuralgia: congenital or acquired narrowing of the infraorbital canal or infraorbital foramen is among the factors contributing to peripheral trigeminal neuralgia.

Class and exam questions

What else to study on this topic

• Maxilla (Maxilla)
• Maxillary nerve (n. maxillaris)
• Pterygopalatine fossa (Fossa pterygopalatina)
• Infraorbital anesthesia

Other topics in the "Anatomical Structures" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.