The third pharyngeal arch is associated with which cranial nerve?

The third pharyngeal arch is associated with which cranial nerve?

• A. CN V
• B. CN VII
• C. CN IX
• D. CN X

Answer: (C)

The third pharyngeal arch is linked to the glossopharyngeal nerve (cranial nerve IX). This arch gives rise to the stylopharyngeus muscle, which is the only pharyngeal arch muscle innervated by CN IX. It also contributes to sensory innervation of the posterior one-third of the tongue via the same nerve. That pairing—third arch derivatives with CN IX—is why this nerve is the correct association. For context, the first arch is innervated by the trigeminal nerve (CN V), the second arch by the facial nerve (CN VII), and the fourth and sixth arches by the vagus nerve (CN X).

The third pharyngeal arch is linked to the glossopharyngeal nerve (cranial nerve IX). This arch gives rise to the stylopharyngeus muscle, which is the only pharyngeal arch muscle innervated by CN IX. It also contributes to sensory innervation of the posterior one-third of the tongue via the same nerve. That pairing—third arch derivatives with CN IX—is why this nerve is the correct association.

For context, the first arch is innervated by the trigeminal nerve (CN V), the second arch by the facial nerve (CN VII), and the fourth and sixth arches by the vagus nerve (CN X).