A 20-year-old woman presents to the emergency department immediately after falling 10 feet off a ladder. On presentation, she has a Glasgow Coma Score of 15 and complains of left sided head pain. CT scan indicates a left frontoparietal epidural hematoma. She then develops right lower extremity weakness. Her pupils are equally round and reactive to light at this time.
A) Left anterior cerebral artery compression
The pressure from this patient’s epidural hematoma has likely caused a subfalcine herniation, resulting in compression of the vasculature controlling her right lower extremity. The lower extremities are controlled by the contralateral medial motor cortex, which is fed by the anterior cerebral artery (ACA). Therefore, this patient’s right leg weakness is most likely a result of left ACA compression.
Answer choice B: Left middle cerebral artery compression, is incorrect. This would manifest as right-sided upper extremity and/or facial weakness.
Answer choice C: Right anterior cerebral artery compression, is incorrect. This would manifest as left-sided lower extremity weakness.
Answer choice D: Right middle cerebral artery compression, is incorrect. This would manifest as left-sided upper and/or facial weakness.
Answer choice E: Uncal herniation, is incorrect. This would injure the patient’s cranial nerves and would likely present with an abnormal pupillary reflex.
Key Learning Point
The anterior cerebral artery feeds the part of the motor cortex that controls the contralateral lower extremity, while the middle cerebral artery feeds the part that controls the contralateral upper extremity and face.
