Ciliarganglion

The ciliary ganglion is a small oval parasympathetic ganglion in the orbit. It forms part of the ocular parasympathetic pathway and is associated with the oculomotor nerve (CN III). Preganglionic parasympathetic fibers from the inferior division of CN III travel in the oculomotor nerve to the ganglion, where they synapse on postganglionic neurons. Postganglionic fibers then join the short ciliary nerves to reach the targeted ocular muscles.

The ganglion lies in the posterior orbit, near the optic nerve, and is connected to the nasociliary nerve by sensory and sympathetic roots. A sensory root carries general sensory fibers from the cornea and ciliary body, derived from the nasociliary nerve. Sympathetic fibers originating in the superior cervical ganglion pass through the ganglion (without synapsing) to reach the dilator pupillae and blood vessels via the long and short ciliary nerves.

The postganglionic parasympathetic fibers innervate the sphincter pupillae and the ciliary muscle, constricting the pupil and enabling near vision through accommodation.

Dysfunction of the ciliary ganglion can impair pupillary constriction and accommodation. Lesions may produce pupil abnormalities such as light-near dissociation or a tonic pupil, depending on the extent and nature of involvement.