The brain receives its arterial blood supply from the internal carotid arteries and vertebral arteries. The internal carotid artery enters the cranium and gives off branches including the anterior cerebral artery and middle cerebral artery. The vertebral arteries join to form the basilar artery which splits into the posterior cerebral arteries. These arteries anastomose to form the Circle of Willis, which provides an alternative blood supply if one of the arteries is occluded. Occlusion of specific arteries can cause deficits in regions supplied by that artery.

1. Blood supply of the Brain
BY:HINAKHALID

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

5. Branches from ICA
• 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: supplies
choroid plexus of temporal horn of lateral
ventricles and other areas including optic
tract, uncus, hippocampus, lateral
geniculate nucleus, etc.

7. 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)

8. 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)

9. • 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.

10. • 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)

13. Anterior Cerebral A
• Occlusion of anterior cerebral artery
• contralateral paralysis and sensory deficits
in the leg and perineum, urinary
incontinence. Often with mental confusion.

14. Vertebrobasilar system
• Vertebral artery, branch from the subclavian
artery, joins together to form the basilar artery.
The latter artery splits into posterior cerebral
arteries.

15. Vertebrobasilar system
• 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.

17. 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.

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

20. 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.

21. 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.
•

22. • 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