Nerves of Orbit Anatomy
1. Trochlear nerve (IV)
2. Ophthalmic nerve (V1)
3. Optic nerve (II)
4. Oculomotor nerve (III)
5. Abducent nerve (VI)
6. Trigeminal (semilunar) ganglion
7. Frontal nerve
8. Lacrimal nerve
9. Supra-orbital nerve
Comment: The sensory innervation to the orbit arises from the ophthalmic division of the trigeminal nerve. The major nerves of this division include the nasociliary, frontal, and lacrimal nerves. The sensory nerve cell bodies reside in the trigeminal (semilunar) ganglion.
The motor innervation of the extra-ocular muscles comes from the oculomotor, trochlear, and abducent nerves.
The optic nerve leaves the orbit via the optic canal. CN III, CN IV, CN V1, and CN VI traverse the superior orbital fissure.
Clinical: The ophthalmic division of the trigeminal nerve (CN V1) is the smallest division of CN V. In addition to its sensory role and, similar to the other 2 divisions of the trigeminal nerve, this division carries autonomic fibers to the eyeball via its nasociliary nerve and connections to the ciliary ganglion (long and short ciliary nerves). Additionally, it carries parasympathetics from the facial nerve (CN VII) that join the lacrimal branch and innervate the lacrimal glands, which produce tears that moisten the cornea of the eyeball. Orbital trauma or infections in this confined compartment may affect these important autonomic pathways.