Which cranial nerve mediates eyelid closure?

• A. Cranial nerve III
• B. Cranial nerve V
• C. Cranial nerve VII
• D. Cranial nerve IX

Answer: (C)

Eyelid closure is accomplished by the orbicularis oculi muscle, which is innervated by the facial nerve. This motor pathway makes the eyelids close during blinking or when you gently force them shut. The muscle that opens the eyelid, the levator palpebrae superioris, is controlled by the oculomotor nerve, so a lesion there would impair opening rather than closing. The trigeminal nerve provides sensation to the eye area and motor to muscles of mastication, not eyelid closure, and the glossopharyngeal nerve has no role in eyelid movement. In reflex blinking, the efferent limb is still VII, reinforcing that the facial nerve mediates eyelid closure.