Ischemic stroke Quiz: Ace Your Exams

A 68-year-old right-handed man is brought to the emergency department following sudden onset weakness in his right arm and dysarthria. The patient’s partner states, “He suddenly dropped his cup of coffee while walking to the kitchen table and was unable to respond to me, so I called 911.” Past medical history includes hypertension and hyperlipidemia for which he takes lisinopril and atorvastatin, respectively. Temperature is 37°C (98.6°F), pulse is 92/min, and blood pressure is 158/104 mmHg. The patient is alert but appears frustrated by not being able to speak. The patient blinks on command. Physical examination demonstrates full visual fields without deficits. Neurologic evaluation demonstrates 2/5 strength in the right upper extremity and 4/5 strength in the right lower extremity. Pathology to which of the following anatomic structures is the most likely etiology of this patient’s clinical condition?