The parasympathetic innervation reaches the middle ear through which nerve via which ganglion?

The parasympathetic innervation reaches the middle ear through which nerve via which ganglion?

• A. Facial nerve via the pterygopalatine ganglion
• B. Glossopharyngeal nerve via otic ganglion
• C. Vagus nerve via nodose ganglion
• D. Trigeminal nerve via trigeminal ganglion

Answer: (A)

Parasympathetic innervation of the middle ear comes from the facial nerve pathway. Preganglionic parasympathetic fibers originate in the superior salivatory nucleus and travel with the greater petrosal nerve, which joins the deep petrosal nerve to form the nerve of the pterygoid canal. They synapse in the pterygopalatine ganglion. From there, postganglionic fibers distribute to the mucosa of the middle ear (via connections to the tympanic region) through branches accompanying the nasal/pharyngeal pathways. This route fits with the pattern of facial nerve parasympathetics targeting various mucosal sites via the pterygopalatine ganglion. In contrast, the glossopharyngeal nerve uses the otic ganglion (via the lesser petrosal nerve) to reach the parotid gland, and the vagus or trigeminal pathways do not provide this middle ear parasympathetic route. Hence, the correct description is the facial nerve through the pterygopalatine ganglion.

Parasympathetic innervation of the middle ear comes from the facial nerve pathway. Preganglionic parasympathetic fibers originate in the superior salivatory nucleus and travel with the greater petrosal nerve, which joins the deep petrosal nerve to form the nerve of the pterygoid canal. They synapse in the pterygopalatine ganglion. From there, postganglionic fibers distribute to the mucosa of the middle ear (via connections to the tympanic region) through branches accompanying the nasal/pharyngeal pathways. This route fits with the pattern of facial nerve parasympathetics targeting various mucosal sites via the pterygopalatine ganglion.

In contrast, the glossopharyngeal nerve uses the otic ganglion (via the lesser petrosal nerve) to reach the parotid gland, and the vagus or trigeminal pathways do not provide this middle ear parasympathetic route. Hence, the correct description is the facial nerve through the pterygopalatine ganglion.