Blood Supply to Brain

1. Blood supply of the Brain

2. Arterial Blood Supply
• Arterial blood supply of the brain
• Brain is supplied by pairs of internal
carotid artery and vetebral artery.

3. Internal Carotid Artery
• Internal carotid artery: branch off from
common carotid artery, enters brain from
carotid canal, splits into middle and
anterior cerebral artery under the anterior
perforated substance
• Before internal carotid artery splits into the
terminal branches, it gives off:

4. Branches from ICA
• 1). Hypophysial arteries: further splits into
– anterior hypophysial artery: supply hypothalamus. The anterior
hypophysial artery breaks into capillaries forming the hypophyseal
portal veins which convey hormones from hypothalamus into anterior
pituitary.
– posterior hypophysial artery: supply neural lobe of the pituitary
• 2). Ophthalmic artery: supply eyes, paranasal sinuses and
parts of the nose
• 3). Posterior communicating artery: runs backward to join
the posterior cerebral artery
• 4). Anterior choroidal artery: supply choroid plexus of
temporal horn of lateral ventricles and other areas including
optic tract, uncus, hippocampus, lateral geniculate nucleus,
etc.

6. Occlusion of internal carotid artery
• 1. ipsilateral blindness (ophthalmic A)
2. half vision of the contralateral eye
(infarction of optic nerve, lateral geniculate
body supplied by anterior choroidal A)

7. Terminal Branches
• Middle Cerebral Artery:
– bigger branch of the two terminal branches
– It branches off frontal, parietal, and temporal branches supplying
primary motor and premotor cortex, frontal eye field, primary
somatosensary area. Left middle cerebral artery supplies
language center.
– Occlusion of middle cerebral artery: paralysis of face, arm,
aphasia (language center)
• Anterior Cerebral Artery:
– meets together to form anterior communicating artery before
they join, gives off recurrent artery of Heubner, also called
medial straite artery, supplies corpus striatum.
– It then ascends along the longitudinal fissure then bends
backward around the genu of the corpus callosum. It branches
into pericallosal artery, along the upper surface of corpus
callosum and callosomarginal artery follows the cingulate sulcus,
which has three branches (anterior medial frontal, medial frontal
medial, and posterior medial frontal)

10. Vertebrobasilar system
• Vertebral artery, branch from the subclavian
artery, joins together to form the basilar artery.
The latter artery splits into posterior cerebral
arteries.
• Branches off the vertebral artery
1. spinal artery: anterior spinal artery: one
formed by branches from each vertebral artery
2. posterior spinal artery: one on each side
3 . posterior inferior cerebellar artery (PICA)
largest branch off vertebral artery, supplies
cerebellar hemisphere, inferior vermis, etc.

12. Basilar artery
• Branches off basilar artery
• 1. anterior inferior cerebellar artery (AICA)
supplies inferior surface of the cerebellum
2. labyrinthine artery supplies the membranous
labyrinth of the internal ear
3. Pontine arteries supply pons and pontine
tegmentum
4. superior cerebellar artery supplies pons,
superior cerebellar peduncle, and inferior
colliculus, etc.

14. Basilar artery
• Occlusion of basilar artery: basilar artery:
coma, die soon, loss control of respiration
center labyrinthine artery: deaf, vestibular
dysfunction (vertigo, fall)

15. Posterior cerebral artery
• Posterior cerebral artery gives off
– 1. Posterior medial central artery
– 2. temporal artery: temporal lobe
– 3. calcarine artery: supplies primary and
association cortex for vision
– 4. parietooccipital branches: parietal and
occipital lobes
– 5. posterior choroidal artery: choroid plexus
located at central part of the lateral ventricle,
third ventricle, etc.

16. Circle of Willis
• Consists:
– anterior communicating, anterior cerebral, internal carotid (short
segment), posterior communicating, and posterior cerebral
arteries. Normally not too much blood flow, could be served as
alternative route if one of the artery in occluded.
• Common site for aneurysms, terminal part of internal
carotid artery anterior communicating artery proximal of
middle cerebral artery
• Groups of arteries arise from the circle
– 1. anteromedial group: branch from anterior cerebral and
communicating artery provides blood to hypothalamus
– 2. anterolateral group: branch from middle cerebral artery
– 3. posteromedial: branches from posterior cerebral and posterior
communicating arteries