Trauma to the infraorbital region (below the eye) would affect which nerve, and what is its function?

Correct answer: A. Infraorbital nerve — purely sensory (lower eyelid, cheek, upper lip, lateral nose)

• A. Correct. The infraorbital nerve is a branch of the maxillary division of the trigeminal nerve (CN V2). It exits through the infraorbital foramen and provides SENSORY innervation ONLY to: the lower eyelid, cheek, upper lip, and lateral nose. It does NOT supply any muscles — it is purely sensory.
• B. The zygomatic nerve (CN V2 branch) provides sensory innervation to the cheek and temporal area — it does not cause the specific infraorbital presentation described.
• C. The facial nerve (zygomatic branch) supplies motor innervation to orbicularis oculi — this would not be affected by trauma to the infraorbital region.
• D. The infraorbital nerve is purely sensory — it does not innervate any muscles. The levator labii superioris is innervated by the zygomatic and buccal branches of the facial nerve (CN VII).