mrcem2-1197

A 28 year old male is brought to the emergency department by his partner due to increasing drowsiness. The patient’s partner informs you that the patient was involved in a physical altercation approximately 40 minutes ago. The patient was struck in the temple and experienced a brief loss of consciousness for about 20 seconds. Initially, the patient appeared to be fine, but after approximately 20 minutes, he started to become progressively more drowsy. A CT scan reveals the presence of an extradural hematoma.

Which vascular structure is typically injured as the underlying cause of an extradural hematoma?