Innervation of the orbicularis oris muscle (controls lip movement/closure) is provided by:

Correct answer: D. Buccal branch of the facial nerve (CN VII)

• A. The ophthalmic nerve (V1) provides sensory innervation to the upper face, forehead, and cornea — not the lips.
• B. The trigeminal nerve (CN V) provides SENSORY innervation to the lips (infraorbital for upper, mental nerve for lower) — NOT motor to facial muscles.
• C. The marginal mandibular branch of CN VII innervates the lower lip depressors (depressor anguli oris, depressor labii inferioris, mentalis) — NOT the orbicularis oris primarily.
• D. Correct. The orbicularis oris (the sphincter muscle of the lips) is innervated by the BUCCAL BRANCH of the facial nerve (CN VII). The facial nerve provides motor innervation to all muscles of facial expression. The buccal branch specifically innervates the upper lip and buccal area muscles.