The muscles of the second arch retain their original nerve supply from which nerve?

The muscles of the second arch retain their original nerve supply from which nerve?

• A. Trigeminal nerve
• B. Facial nerve
• C. Glossopharyngeal nerve
• D. Vagus nerve

Answer: (B)

Muscles from the second pharyngeal arch are innervated by the facial nerve (cranial nerve VII). This arch gives rise to the muscles of facial expression, as well as the stapedius, stylohyoid, and the posterior belly of the digastric, all of which retain VII as their motor supply. The pattern matches how each arch has its own destined nerve: the first arch by the trigeminal nerve, the third arch by the glossopharyngeal nerve, and the fourth and sixth arches by the vagus nerve. So the correct innervation for the second arch muscles is the facial nerve.

Muscles from the second pharyngeal arch are innervated by the facial nerve (cranial nerve VII). This arch gives rise to the muscles of facial expression, as well as the stapedius, stylohyoid, and the posterior belly of the digastric, all of which retain VII as their motor supply. The pattern matches how each arch has its own destined nerve: the first arch by the trigeminal nerve, the third arch by the glossopharyngeal nerve, and the fourth and sixth arches by the vagus nerve. So the correct innervation for the second arch muscles is the facial nerve.