BLood Supply To The Brain

Question 1

What are the sources of arterial blood to the brain

Answer 1

o The anterior circulation is fed by the internal carotid arteries and supplies most of the cerebral hemispheres - middle cerebral artery and anterior cerebral artery
o The posterior circulation is fed by the vertebral arteries and supplies the
brainstem, cerebellum, some of the temporal lobe and the occipital lobe - basilar artery, vertebral arteries

Question 2

Describe the middle cerebral artery

Answer 2

o Middle cerebral artery
 The direct continuation of the internal carotid artery
 Cortical branches emerge from the lateral fissure to supply the lateral
aspect of the cerebral hemisphere (cortex and underlying white matter), including lateral parts of the frontal and parietal lobes as well as the superior temporal lobe
 Deep branches (the lenticulostriate arteries) supply deep grey matter structures including the lentiform nucleus and caudate as well as the internal capsule

Question 3

Describe the anterior cerebral artery

Answer 3

 A branch of the internal carotid artery
 The left and right anterior cerebral arteries anastomose in the midline
via the anterior communicating artery
 The vessels loop over the corpus callosum and send branches to the
adjacent cortex
 Cortical branches supply the medial aspect of the frontal and parietal
lobes (not the occipital lobe)
 There are also branches to the corpus callosum itself

Question 4

Describe the basilar artery

Answer 4

o Basilar artery
 Midline vessel formed from the confluence of the vertebral arteries
 Has a number of major branches

Question 5

What are the major branches of the basilar artery and what do they supply

Answer 5

• Terminal bifurcation gives rise to the posterior cerebral artery o Supplies occipital lobe, inferior temporal lobe and
thalamus (via thalamoperforator and
thalamogeniculate branches)
o Also supplies midbrain en passant
o Posterior communicating arteries branch from these to
connect with the anterior circulation (internal carotid artery)

• Superior cerebellar artery supplies the superior aspect of the cerebellum and midbrain en passant
• Pontine arteries supply the pons (including descending corticospinal fibres)
• Anterior inferior cerebellar artery the supplies the antero- inferior aspect of the cerebellum and lateral pons en passant

Question 6

Desribe the vertebral arteries

Answer 6

o The vertebral arteries give rise to two important branches to the brain
 Anterior spinal arteries converge in the midline to supply the anterior
2/3 of the spinal cord
 Posterior inferior cerebellar arteries supply the postero-inferior
aspect of the cerebellum en passant