Review Question - QID 107914

A 65-year-old female with a past medical history of hypertension presents to her primary care doctor with a 3 month history of spasmodic facial pain. The pain is located in her right cheek and seems to be triggered when she smiles, chews, or brushes her teeth. The pain is sharp and excruciating, lasts for a few seconds, and occurs up to twenty times per day. She denies headaches, blurry vision, facial weakness, or changes in her memory. She feels rather debilitated and has modified much of her daily activities to avoid triggering the spasms. In the clinic, her physical exam is within normal limits. Her primary care doctor prescribes carbamazepine and asks her to follow up in a few weeks. Which cranial nerve is most likely involved in the patient's disease process?