Which autonomic ganglion is associated with CN III?

• A. Ciliary
• B. Pterygopalatine
• C. Otic
• D. Submandibular

Answer: (A)

The main concept here is that cranial nerves carrying parasympathetic fibers have specific autonomic ganglia in the head where their preganglionic fibers synapse before reaching the target to modulate pupil size and lens shape.

For the oculomotor nerve (CN III), the preganglionic parasympathetic fibers originate in the Edinger-Westphal nucleus and travel with CN III to a small ganglion in the posterior orbit. That ganglion is the ciliary ganglion. After synapsing there, the postganglionic fibers ride the short ciliary nerves to innervate the sphincter pupillae (pupil constriction) and the ciliary muscle (accommodation for near vision).

The other listed ganglia are associated with different nerves: the pterygopalatine ganglion with the facial nerve for lacrimal glands and mucosal glands; the otic ganglion with the glossopharyngeal nerve for the parotid gland; and the submandibular ganglion with the facial nerve for submandibular and sublingual glands. So the ganglion linked specifically to CN III is the ciliary ganglion.