The ciliary ganglion is a ganglion located in the region of the Orbit. The ciliary ganglion has a diameter of only 1-2 mm. It is located within the orbit approximately 2 cm behind the eyeball. It lies between the Lateral rectus muscle and the Optic nerve. Sensory, sympathetic, and parasympathetic fibers pass through the ciliary ganglion, although only the latter synapse in the ganglion. For the sensory and sympathetic fibers, the ganglion is merely a way station. All fibers leaving the ganglion pass through the short ciliary nerves into the interior of the eye[^1].
Parasympathetic fibers
The parasympathetic fibers of the ciliary ganglion originate from the accessory oculomotor nucleus. They travel with the Oculomotor nerve through the superior orbital fissure into the orbit, where they enter the ganglion as the oculomotor root. They synapse here with the postganglionic fibers and provide visceromotor innervation to the smooth muscle of the intrinsic muscles of the eye, the ciliary muscle, and the sphincter pupillae.
Sympathetic fibers
The postganglionic sympathetic fibers of the ciliary ganglion originate from neurons of the superior cervical ganglion. They reach the ganglion via the internal carotid plexus and travel without synapsing to the dilator pupillae muscle, the orbitalis muscle, and the tarsal muscles.
Sensory fibers
Some sensory fibers from the nasociliary nerve pass through the ciliary ganglion as the long root of the ciliary ganglion. They supply the cornea and conjunctiva.
