Which nerves elicit secretion from the parotid gland?

Which nerves elicit secretion from the parotid gland?

• A. Tympanic branch of CN IX; lesser petrosal
• B. Chorda tympani; greater petrosal
• C. Glossopharyngeal nerve; lesser petrosal
• D. Auriculotemporal nerve

Answer: (A)

Parasympathetic fibers that stimulate the parotid gland start in the glossopharyngeal nerve and take a specific route: they leave CN IX as the tympanic branch (Jacobson’s nerve), ascend to form the tympanic plexus in the middle ear, then continue as the lesser petrosal nerve to reach the otic ganglion. From there postganglionic fibers ride with the auriculotemporal nerve to reach the parotid and trigger secretion. So the nerves most directly involved in initiating parotid secretion are the tympanic branch of CN IX and the lesser petrosal nerve. Other options point to nerves that innervate different glands or represent only part of the pathway (the postganglionic carrier), not the primary preganglionic route to the parotid.

Parasympathetic fibers that stimulate the parotid gland start in the glossopharyngeal nerve and take a specific route: they leave CN IX as the tympanic branch (Jacobson’s nerve), ascend to form the tympanic plexus in the middle ear, then continue as the lesser petrosal nerve to reach the otic ganglion. From there postganglionic fibers ride with the auriculotemporal nerve to reach the parotid and trigger secretion. So the nerves most directly involved in initiating parotid secretion are the tympanic branch of CN IX and the lesser petrosal nerve. Other options point to nerves that innervate different glands or represent only part of the pathway (the postganglionic carrier), not the primary preganglionic route to the parotid.