External nasal nerve: sensation of the tip of the nose
Quick facts
- Origin
- Terminal branch of the anterior ethmoidal nerve, which comes from the nasociliary (V1).
- Function
- Sensory: skin of the tip, ala and lower dorsum of the nose.
- Exit
- Emerges between the nasal bone and the upper lateral cartilage.
- Clinical sign
- Herpes zoster lesions on the tip of the nose (Hutchinson's sign) indicate involvement of the nasociliary nerve.
The external nasal nerve is a sensory branch that carries the sensation of touch, pain and temperature to the skin of the tip, ala and lower dorsum of the nose. It is the final branch of the anterior ethmoidal nerve, which arises from the nasociliary, itself a branch of the ophthalmic (V1) of the trigeminal.
What is its course?
The anterior ethmoidal nerve leaves the orbit, passes through the nasal cavity and descends along the side of the nose, on the inside. Near the end, it emerges on the face between the lower margin of the nasal bone and the upper lateral cartilage, where it becomes the external nasal nerve. From there it spreads small branches across the skin of the tip and lower dorsum. The cartilages of the nose lie just beneath this path.
The lateral and upper part of the nose is supplied by other nerves, including the infraorbital, from V2.
| Region of the nose | Main innervation |
|---|---|
| Root and upper dorsum | Infratrochlear and supratrochlear |
| Tip, ala and lower dorsum | External nasal (V1) |
| Side and base of the ala | Infraorbital (V2) |
Why does it matter in practice?
The nose is one of the highest vascular risk regions. The skin is thin, blood supply depends on terminal vessels such as the dorsal nasal artery and the lateral nasal artery, and there are anastomoses with the ophthalmic territory. The external nasal nerve enters the story in three ways.
- Pain as a warning sign: the tip of the nose has well-represented sensation, and intense, persistent pain there after a procedure is a sign that must not be dismissed. If vascular compromise is suspected, stop, reassess and act according to the service protocol.
- Herpes zoster and Hutchinson's sign: vesicles on the tip or side of the nose indicate involvement of the nasociliary nerve, which also supplies the cornea. The patient needs prompt medical assessment, not an aesthetic procedure.
- Numbness after nasal interventions: surgery and manipulation of the tip can leave altered sensation for months, which matters in the history of anyone who has had a rhinoplasty.
How does it fit into planning?
Any assessment of the nose starts with the medical history: prior surgery, prior filler, recurrent herpes and any history of altered sensation. The nasal tip is both an aesthetic structure and a delicately innervated area, which is why many services handle the topic with extra caution and detailed consent.
Also called: external nasal branch, nervus nasalis externus.
Frequently asked questions
What is Hutchinson's sign?
It is the appearance of vesicles on the tip or side of the nose in herpes zoster. It indicates involvement of the nasociliary nerve and a higher chance of eye involvement, which calls for prompt assessment.