An upper motor neuron lesion of CN VII due to cerebral stroke affects which part of the face?

• A. Forehead only on the affected side
• B. Lower contralateral muscles of the face but not the forehead
• C. Entire face on the affected side
• D. Ipsilateral forehead and eye closure

Answer: (B)

When the corticobulbar pathways to the facial nerve are damaged above the facial nucleus, the upper face keeps input from both sides while the lower face relies mainly on the opposite hemisphere. A stroke causing an upper motor neuron lesion therefore weakens the muscles of the lower half of the opposite side of the face, sparing the forehead. This pattern—contralateral lower facial weakness with preserved forehead movement—distinguishes it from a peripheral (lower motor neuron) CN VII lesion, which would affect the entire ipsilateral face, including the forehead, eye closure, and mouth. So the impact is on the lower contralateral facial muscles, with the forehead spared.