Ciliary ganglion

The ciliary ganglion is one of four parasympathetic ganglia of the head and neck. It receives parasympathetic fibers from the oculomotor nerve.

smallest of the ganglia (2 mm in size)
located posterolaterally in the intraconal space of the orbit (towards the orbital apex) between the optic nerve and the lateral rectus muscle
just lateral to the ophthalmic artery as it crosses the optic nerve from lateral to medial

parasympathetic root (fibers synapse in the ganglion)
- from the Edinger-Westphal nucleus of the oculomotor nerve (III)
sympathetic root (fibers pass through the ganglion without synapsing)
- from the ICA (from the superior cervical ganglion) via the nasociliary nerve (V1)
sensory root (fibers pass through the ganglion without synapsing)
- via the small communicating branch of the ciliary ganglion (from nasociliary - V1)

~12 or more branches, termed short ciliary nerves
each contains elements from all 3 roots (above), and pierce back of sclera around attachment of optic nerve to supply the globe
the vast marjority of fibers from ganglionic cells supply ciliary body (accommodation); only ~3% supply sphincter pupillae
note; while both long and short ciliary nerves contain sensory/sympathetic supply to the cornea, iris, and ciliary body; only short ciliary are involved in pupillary constriction and accommodation

pathology of the ciliary ganglion can produce a tonic pupil, where the pupil does not react to light and slowly accommodates
Adie syndrome: when a non-reactive, slowly accomodating pupil is associated with absent deep tendon reflexes and diaphoresis