Which pharyngeal arch forms the muscles of facial expression?

• A. First pharyngeal arch
• B. Second pharyngeal arch
• C. Third pharyngeal arch
• D. Fourth pharyngeal arch

Answer: (B)

Muscles that move the face develop from the mesoderm of the second pharyngeal arch, the hyoid arch. These muscles attach to the skin of the face and scalp to create expressions, and they are innervated by the facial nerve (cranial nerve VII). This link to the second arch is why it’s the source of the facial expression muscles. Other arches contribute to different muscle groups—first arch to muscles of mastication, third arch to stylopharyngeus, fourth arch to pharyngeal constrictors and most intrinsic laryngeal muscles—so the distinctive origin of facial expression muscles is the second arch.