Nasociliary nerve: trigeminal branch for the eye and nose
Quick facts
- Origin
- Branch of the ophthalmic nerve (V1), the third branch after the frontal and lacrimal.
- Entry into the orbit
- Through the superior orbital fissure, inside the muscle cone.
- Main branches
- Anterior and posterior ethmoidal, infratrochlear and long ciliary nerves.
- Territory
- Cornea, nasal mucosa, dorsum and tip of the nose, medial corner of the eye.
The nasociliary nerve is one of the three main branches of the ophthalmic nerve (V1), the upper division of the trigeminal. It carries sensation from the cornea, nasal mucosa, dorsum and tip of the nose, and the medial corner of the eye. It is purely sensory.
What is its course?
The nasociliary nerve enters the orbital cavity through the superior orbital fissure, inside the cone formed by the muscles that move the eye. It then crosses the optic nerve and runs along the medial wall of the orbit, where it divides into branches.
| Branch | Where it goes |
|---|---|
| Long ciliary | Eyeball, including the cornea |
| Posterior ethmoidal | Ethmoid and sphenoid sinuses |
| Anterior ethmoidal | Nasal cavity; ends as the external nasal nerve |
| Infratrochlear | Medial corner of the eye and nasal root |
The point to remember is the link between the tip of the nose and the eye. Both depend on the same nerve, and that has very concrete clinical consequences.
Why does it matter in facial harmonization?
- Hutchinson's sign: in herpes zoster of the ophthalmic branch, vesicles on the tip or side of the nose indicate involvement of the nasociliary nerve and a higher risk to the cornea. Anyone who sees a patient with a lesion there should refer them, not perform a procedure.
- Vascular risk map: the nasociliary territory partly overlaps that of the ophthalmic artery and its branches, such as the dorsal nasal artery. Pain in the eye, nasal root or nasal tip after a procedure in the glabella or nose can signal a vascular problem.
- Anesthesia of the area: numbness of the nasal root and medial canthus after local blocks is expected, due to anesthetizing the infratrochlear and supratrochlear nerves.
- Medical history: a history of herpes around the eye, uveitis or keratitis contraindicates or changes the timing of any intervention near the orbit.
What to know without getting into technique?
The nasociliary nerve is review knowledge: it helps explain why nasal pain can relate to the eye and why the skin of the tip is so sensitive. A public page does not teach where or how to inject. The technical decision belongs to the qualified professional, according to the rules of their professional council (in Brazil).
Also called: nasociliary branch of V1, nervus nasociliaris.
Frequently asked questions
Why is the nasociliary nerve mentioned when talking about herpes zoster?
Because it supplies the tip of the nose and the cornea. Vesicles on the tip of the nose (Hutchinson's sign) indicate a risk of eye involvement and call for prompt medical assessment.