Neuroanatomy USMLE Step 1 Practice Question
A 55-year-old woman comes to the physician because of a 5-month history of weakness of the left side of her face, loss of taste, as well as dryness and redness of her left eye. She has no history of serious illness and takes no medications. Physical examination shows an inability to puff the left cheek and close her left eye. An MRI of the brain shows a contrast-enhancing mass in the posterior fossa. The patient's symptoms are most likely caused by compression of which of the following structures?
Answer choices
- AStructure A (trochlear nerve, CN IV)
- BStructure B (trigeminal nerve, CN V)
- CStructure C (abducens nerve, CN VI)
- DStructure D (facial nerve, CN VII)Correct answer
- EStructure E (vestibulocochlear nerve, CN VIII)
- FStructure F (accessory nerve, CN XI)
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.