Neuroanatomy USMLE Step 1 Practice Question

A 45-year-old man presents to the emergency department with acute-onset left facial weakness and is unable to close his left eye completely. On examination, he has loss of taste sensation on the anterior two-thirds of the left tongue and reports that normal environmental sounds seem unusually loud in the left ear. His vital signs are stable and non-contributory. Otoscopic examination reveals no cerumen impaction, perforation, or inflammation. Audiometry confirms sensorineural hyperacusis on the left. Brain MRI with and without contrast shows no acute abnormalities. A Weber test is normal. The patient has no history of trauma, ear pain, or recent viral illness. Which of the following anatomical structures is most likely responsible for the constellation of findings in this patient?