Arterial ✏️supply To The Brain

Question 1

What are the two arterial blood sources that supply the brain?

Answer 1

• the anterior circulation fed by the internal carotid arteries -> most of the cerebral hemispheres
• the posterior circulation fed by the vertebral arteries -> Brainstem, cerebellum, some of the temporal lobe,
  & occipital lobe

Question 2

What makes up the anterior circulation?

Answer 2

Middle cerebral artery (continuation of internal carotid A)

Cortical branches emerge from lateral fissure -> lateral aspect of cerebral hemisphere - cortex and underlying white matter (lateral parts of frontal and parietal lobes + superior temporal lobe)

Deep branches (lenticulostriate arteries) -> deep grey matter structures inclu lentiform nucleus + caudate + internal capsule

Anterior cerebral artery (branch of internal carotid A) - left and right cerebral arteries anastomose in midline via anterior communicating A, vessels loop over corpus callosum -> branches adjacent cortex. Cortical branches -> medial frontal/ parietal lobes. Branches -> corpus callosum

Question 3

What makes up the posterior circulation?

Answer 3

Basilar artery - midline vessel (from vertebral arteries) major branches:

• terminal bifurcation -> posterior cerebral artery (occipital lobe, inferior temporal lobe, thalamus)
• supplies midbrain
• posterior communicating arteries branch from these to connect with anterior circulation
• superior cerebellar artery -> superior cerebellum + midbrain
• pontine arteries -> pons
• anterior inferior cerebellar artery -> antero-inferior cerebellum + lateral pons

Vertebral arteries -> anterior spinal arteries converge -> anterior 2/3 spinal cord + posterior inferior cerebellar arteries