The first pharyngeal arch is associated with which cranial nerve?

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

Answer: (A)

The first pharyngeal arch is innervated by the trigeminal nerve, CN V. This arch, also called the mandibular arch, forms structures like the mandible and the muscles of mastication (masseter, temporalis, medial and lateral pterygoids), as well as the tensor tympani, tensor veli palatini, and the mylohyoid and anterior belly of the digastric. The motor supply to these muscles comes from the mandibular division of CN V (V3). Sensory fibers to many tissues derived from this arch travel with CN V as well, including general sensation from the face and oral region (the lingual nerve, a branch of V3, carries general sensation from the anterior two-thirds of the tongue). In contrast, the other arches are associated with different nerves: the second arch with CN VII, the third with CN IX, and the fourth and sixth with CN X. Therefore, CN V is the nerve most closely tied to the first pharyngeal arch.