Chorda tympani is a branch of which cranial nerve?

• A. IX
• B. VII
• C. V
• D. VIII

Answer: (B)

The main idea here is identifying the origin of the chorda tympani. It is a branch of the facial nerve (cranial nerve VII). This slender nerve splits off within the facial canal, travels through the middle ear, and carries taste fibers from the anterior two-thirds of the tongue along with preganglionic parasympathetic fibers to the submandibular ganglion, which then innervate the sublingual and submandibular glands. It then hitchhikes on the lingual nerve (a branch of V3) to reach the tongue. Because its root is the facial nerve, not the glossopharyngeal, trigeminal, or vestibulocochlear nerves, those others have different functions and pathways.