Which arteries supply the brainstem, cerebellum, occipital lobe, posterior temporal lobe and thalamus?

• A. Internal Carotid Arteries
• B. External Carotid Arteries
• C. Vertebral Arteries
• D. Basilar Artery

Answer: (C)

Blood supply to these regions comes from the posterior circulation of the brain. The vertebral arteries merge to form the basilar artery, and from there the posterior cerebral arteries branch off to feed the occipital lobe, posterior temporal lobe, and thalamus. The brainstem and cerebellum are fed by branches of the vertebral and basilar arteries (such as PICA, AICA, and SCA). So the vertebral arteries are the upstream vessels that ultimately supply all these areas, whereas the anterior circulation from the internal and external carotid arteries mainly feeds other regions and does not predominantly supply these posterior structures.