Which cranial nerve innervates the orbicularis oculi to close the eye?

Which cranial nerve innervates the orbicularis oculi to close the eye?

• A. CN III
• B. CN IV
• C. CN VII
• D. CN IX

Answer: (C)

Closing the eyelid is achieved by the orbicularis oculi, a facial expression muscle whose motor supply comes from the facial nerve. The facial nerve, specifically its temporal branch, innervates this muscle, enabling eyelid closure and blinking. This is a somatic motor function distinct from the other cranial nerves listed: the oculomotor nerve mainly controls most extraocular muscles and elevates the eyelid (via the levator palpebrae), the trochlear nerve innervates only the superior oblique, and the glossopharyngeal nerve handles throat and gag-related functions. So the nerve responsible for eyelid closure is the facial nerve.

Closing the eyelid is achieved by the orbicularis oculi, a facial expression muscle whose motor supply comes from the facial nerve. The facial nerve, specifically its temporal branch, innervates this muscle, enabling eyelid closure and blinking. This is a somatic motor function distinct from the other cranial nerves listed: the oculomotor nerve mainly controls most extraocular muscles and elevates the eyelid (via the levator palpebrae), the trochlear nerve innervates only the superior oblique, and the glossopharyngeal nerve handles throat and gag-related functions. So the nerve responsible for eyelid closure is the facial nerve.