Internal carotid artery
USMLE® Step 1 style questions USMLE
A 59-year-old male presents with an intractable headache for the past 12 hours. He was painting his bedroom this morning and had the acute onset of headache accompanied by dizziness and ataxia. He also notes a gradual onset of hemiparesis. On exam, you note ptosis and miosis, without anhydrosis or a facial droop. A lesion in which of the following vessels is the most likely cause of this patient’s symptoms?