Ophthalmic division of the trigeminal nerve (V1)
Division or branch · CN V1 Sensory
The purely sensory upper division runs in the lateral wall of the cavernous sinus and divides into lacrimal, frontal and nasociliary nerves as it passes the superior orbital fissure. It supplies the cornea, conjunctiva, upper eyelid, forehead and scalp back to the vertex, the bridge and tip of the nose, the frontal and ethmoidal sinuses and the tentorium.
Traced from the start
- Midbrain
- Pons
- Oculomotor nerve (CN III)Trochlear nerve (CN IV)Trigeminal nerve (CN V)Abducens nerve (CN VI)
- Superior orbital fissure
- Ophthalmic division of the trigeminal nerve (V1)
Detail
- Sensory
- Cornea and conjunctiva (nasociliary → long ciliary nerves); forehead, upper eyelid and scalp to the vertex (frontal → supraorbital and supratrochlear); tip and dorsum of the nose (nasociliary → external nasal); lateral upper lid (lacrimal)
- Branches
- Lacrimal, frontal, nasociliary (mnemonic LFN); nasociliary also gives the anterior and posterior ethmoidal nerves and the sensory root of the ciliary ganglion
- Reflex
- Afferent limb of the corneal reflex; the efferent limb is VII to orbicularis oculi on both sides
- Carries
- Postganglionic sympathetic fibres to dilator pupillae via the long ciliary nerves; postganglionic parasympathetic fibres to the lacrimal gland arrive on the lacrimal nerve from the zygomatic branch of V2
When it goes wrong
Herpes zoster ophthalmicus: varicella zoster reactivation in the V1 territory
Painful vesicular rash on the forehead, upper lid and scalp stopping at the midline; vesicles on the tip or side of the nose (Hutchinson's sign, nasociliary involvement) predict keratitis and uveitis, so start oral antivirals within 72 hours and refer to ophthalmology
Lesion of V1 or the trigeminal ganglion (cerebellopontine angle tumour, cavernous sinus lesion)
Touching the affected cornea produces no blink in either eye, whereas touching the other cornea makes both blink; in a facial nerve lesion only the eye on the weak side fails to blink whichever cornea is touched
Contact lens abuse or diabetic and herpetic neuropathy blunting corneal sensation
Painless corneal ulceration (neurotrophic keratitis) that presents late
Practise this structure
1 question in the bank tagged Corneal Reflex.