Infraorbital nerve and foramen: anatomy and anesthesia
- Artery
- Nerve
- Highlighted area
Quick facts
- Origin
- Terminal branch of the maxillary nerve (V2), the second division of the trigeminal nerve.
- Foramen
- On the anterior surface of the maxilla, usually about 1 cm below the infraorbital margin, with variation.
- Sensory supply
- Lower eyelid, cheek, lateral wall and ala of the nose, and upper lip.
- Accompanying vessels
- Infraorbital artery and vein, which exit through the same foramen.
- Relevance in HOF
- Landmark in upper lip anesthesia and a neighboring structure for tear trough and medial cheekbone filler.
The infraorbital nerve is the terminal branch of the maxillary nerve (V2), the second division of the trigeminal nerve. It runs along the floor of the orbit and exits onto the face through the infraorbital foramen, an opening on the anterior surface of the maxilla below the eye. It is a sensory nerve: it carries sensation from the lower eyelid, the cheek, the side of the nose and the upper lip. The infraorbital artery and vein exit alongside it.
Where is the infraorbital foramen?
| Reference | Usual description |
|---|---|
| Height | Usually about 1 cm below the infraorbital margin |
| Vertical line | Roughly aligned with the pupil, looking straight ahead |
| Muscle relation | Under the levator labii superioris, above the origin of the levator anguli oris |
| Variation | Position, size and accessory foramina vary between people and between sides |
The infraorbital foramen, the supraorbital foramen and the mental foramen are usually close to the same vertical line, which helps in remembering the anatomy. Even so, that line is approximate, and palpation and knowledge of the variation count for more than the rule.
What does the infraorbital nerve supply?
On leaving the foramen, it fans out into three groups of branches:
- Inferior palpebral: skin and conjunctiva of the lower eyelid.
- External nasal: lateral wall and ala of the nose.
- Superior labial: skin and mucosa of the upper lip, and part of the cheek.
Before exiting, still inside the canal, it gives superior alveolar branches to the teeth and gum of the maxilla. That is why the infraorbital nerve block, used in dentistry, is also cited in anesthesia for upper lip procedures. The block technique is a matter of hands-on training and falls outside this page; the overview is in local anesthesia in HOF.
Why does it matter in HOF?
- Tear trough and medial cheekbone: the foramen is close to the area treated in tear trough and medial cheekbone filler. Compression by volume or direct trauma can cause transient paresthesia.
- Bleeding: the infraorbital artery and vein exit through the same foramen, and the area has thin skin. This explains bruises and ecchymosis in the area.
- Anesthesia: the nerve block is an alternative to infiltrated anesthetic in the upper lip region, at the professional's discretion.
How does it show up in the assessment?
- Prior sensation: ask about numbness or tingling in the cheek and lip before the procedure and record it in the patient record.
- History of fracture or surgery: midface fractures and maxillary surgery may have affected the nerve.
- Palpation: in many people, the foramen can be felt as a small depression below the edge of the orbit.
Also called: infraorbital foramen, nervus infraorbitalis.
Frequently asked questions
Where is the infraorbital foramen?
On the anterior surface of the maxilla, below the lower border of the orbit, usually about 1 cm below it and roughly in line with the pupil when looking straight ahead. The position varies between people and between sides.
What happens if the infraorbital nerve is injured?
There may be tingling, numbness or altered sensation in the lower eyelid, cheek, nasal ala and upper lip on the affected side. In most irritations from compression or mild trauma the condition tends to improve with time, but it needs to be assessed and followed up.