A patient with Bell's palsy: which nerve branch will NOT be affected?

Correct answer: D. Infraorbital nerve

• A. The buccal branch of CN VII innervates the buccinator and upper lip muscles — it IS affected in Bell's palsy, causing inability to smile on the affected side.
• B. The zygomatic branch of CN VII (innervates orbicularis oculi) IS affected in Bell's palsy — patients cannot close their eye on the affected side.
• C. ⚠️ The source lists 'Frontal' as the correct answer (won't be affected). However, the frontal (temporal) branch of CN VII IS affected in Bell's palsy. The question may be referring to the frontal branch of CN V1 (supraorbital/supratrochlear nerves) which are SENSORY and would NOT be affected. If the exam meant frontal branch of V1 = correct. If temporal branch of VII = it IS affected.
• D. The infraorbital nerve is a branch of CN V2 (trigeminal nerve) — it provides SENSORY innervation to the cheek and upper lip. Bell's palsy affects CN VII (facial nerve) ONLY, causing MOTOR weakness. The infraorbital nerve (CN V) is completely separate from CN VII and would NOT be affected by Bell's palsy.