A patient presents with facial drooping on one side but is able to close the eye on the affected side. Which cranial nerve is most likely involved?

This presentation is key to differentiating central from peripheral facial nerve lesions. The forehead and eye-closing muscles (orbicularis oculi) receive bilateral cortical input — both cerebral hemispheres innervate the upper face bilaterally. In a CENTRAL (supranuclear/upper motor neuron) CN VII lesion (e.g., stroke), the upper face is spared because the contralateral hemisphere compensates. The result: the patient can still close their eye (upper face preserved) but has contralateral lower face weakness (droop). In a PERIPHERAL (lower motor neuron/Bell's palsy) CN VII lesion, ALL ipsilateral facial muscles are affected — the patient CANNOT close the eye. The ability to close the eye indicates a central lesion, not peripheral.