BLOOD SUPPLY OF BRAIN

PRESENTER: DR PAWAN KUMAR DR R M L & PGIMER, DELHI

-15% of the cardiac output

-25% of the total oxygen.

-Cerebral blood flow is approximately 50 ml/g/min.

-Supplied by two internal carotid arteries and two vertebral arteries.

AORTIC ARCH1.Innominate artery (IA) /

Brachiocephalic trunk

-Rt subclavian artery (SCA)-

Right vertebral artery

-Rt common carotid artery (CCA)

2.Left Common Carotid Artery (CCA)

3.Left Subclavian Artery (SCA)- Left

Vertebral Artery (VA)

Major Arteries

1.INTERNAL CAROTID--ARCH OF AORTA-INTERNAL +EXTERNAL

CAROTID AT SUPERIOR BORDER OF THYROID CARTILAGE

-ENTER THE BRAIN-CAROTID CANAL

2. VERTEBRAL ARTETIS

-FROM 1st PART OF SUBCLAVIAN ARTERY.

-TRAVERSE FROM C6 TO C1 –FORAMAN MAGNUM

-UNITES TO FORM BASILAR ARTERY AT THE LOWER BORDER OF THE PONS.

INTERNAL CAROTID ARTERY• Four segments:

– Cervical

– Petrous

– Cavernous

– Cerebral / Supraclinoid

• Branches

– Meningohypophyseal trunk

– Ophthalmic artery (OA)

– Superior hypophyseal artery

– Posterior communicating artery (PComA)

– Anterior choroidal artery (AChA)

– Anterior cerebral artery (ACA)

– Middle cerebral artery (MCA) (continuation of the

ICA)

– Cervical segment

– From the bifurcation of CCA

– Extends to the entrance into the carotid foramen of the petrous temporal bone

– No branches

-Petrous Segment

-Extends from base of skull to the petrous apex

-Ascending , Genu, Horizontal

-Enters cranial vault via foramen lacerum.

-Branches - Carotico tympanic A & A of pterygoid canal

Cavernous Segment

-Passes through cavernous sinus with

Abducens Nerve

-Cavernous branches-trigeminal ganglion

-Branches supply posterior pituitary

(Meningohypophyseal Artery)

- Cerebral part

Begins after penetration of dura, continues until bifurcation into ACA & MCA3 Branches: 1.Ophthalmic A2.Posterior Communicating A

3.Anterior Choroidal A--ends in the choroid plexus. -crus cerebri, the lateral geniculate body, the optic tract, and the internal capsule).

Ophthalmic artery1st intradural branch of ICA

Supplies globe, orbit,frontal and ethmoidal sinuses, & frontal scalp

Central retinal A, Long & Short posterior ciliary branches

Branches of Ophthalmic A anastamose with Maxillary A branches - potential for collateral flow in cases of proximal carotid occlusion

Vertebral artery• V1: (extraosseous-origin to c6):

Segmental cervical muscular and spinal branches -

• V2( foraminal- C6 TO C1): : meningeal/muscular/spinal branches

• V3 (extraspinal-C1-dura): Posterior meningeal artery

• V4: (intradural)– Anterior and sometimes posterior

spinal arteries– Perforating branches to medulla– PICA: gives off perforating medullary,

choroid, tonsillar, cerebellar branches

BASILAR ARTERY1.The pontine arteries

2. The labyrinthine

-the internal ear.

- often arises as a branch of the anterior inferior cerebellar artery.

3. The anterior inferior cerebellar artery

the anterior and inferior parts of the cerebellum .

A few branches pass to the pons and the upper part of the medulla oblongata.

4. The superior cerebellar artery arises close to the termination of the basilar

artery

the superior surface of the cerebellum, pons, the pineal gland, and the superior

medullary velum, tela chorde of third ventricle.

5.The posterior cerebral (in interpeduncular cistern)

CIRCLE OF WILLIS

-In the interpeduncular fossa at the base of the brain.

- It is formed by the anastomosis between the two internal

carotid arteries and the two vertebral arteries

perforating arteries from the circle of Willis or from vessels near

• four principal groups

1.anteromedial group-the optic chiasma; lamina terminalis;

anteriorpreoptic and supraoptic areas of the hypothalamus;

septum pellucidum; paraolfactory areas; anterior columns of

the fornix; cingulate gyrus; rostrum of the corpus callosum;

anterior part of the putamen and head of the caudate

nucleus.

2-The posteromedial group-the hypothalamus and pituitary and

the anterior and medial parts of the thalamus via

thalamoperforating arteries ,the mammillary bodies,

subthalamus, lateral wall of the third ventricle, the medial

thalamus, and globus pallidus.

3-The anterolateral group (lenticulostriate arteries)-posterior

striatum, lateral globus pallidus and internal capsule.

4-The posterolateral -the cerebral peduncle, colliculi, pineal

gland and posterior thalamus and medial geniculate body.

Anterior cerebral Artery

Three segments:

A1 –Pre communicating segmentMedial lenticulostriate

branches

A2-Post communicating segmentRecurrent artery of HeubnerOrbitofrontalFrontopolar

A3- distal ACA / cortical branchesPericallosalCallosomarginal

ACA SupplyThe cortical branches.

-Two or three orbital branches supply the olfactory cortex, gyrus rectus and medial orbital

gyrus.

-Frontal branches supply the corpus callosum, cingulate gyrus, medial frontal

gyrus and paracentral lobule.

- Parietal branches supply the precuneus

- the frontal and parietal supply a strip of territory on the superolateral surface that represent

the lower limb.

CENTRAL BRANCHES:

-they supply the rostrum of the corpus callosum, the septum pellucidum, the anterior part of

the putamen, the head of the caudate nucleus and adjacent parts of the internal capsule

Middle cerebral ArteryFour segments:

• M1- horizontal / sphenoidal segment:

The stem of MCA 5-15

lenticulostriate branches

• M2- insular segment:

Runs deep in sylvian fissure and along

insula ; Superior & Inferior divisions

• M3- opercular segment:

Follows the curvature of operculum

and ends as terminal branches of MCA

• M4- cortical branches:

Terminal segment

Middle cerebral Artery•M1- Horizontal segment•Lateral Lenticulostriate•M2- Insular segment•M3- Opercular segment•Opercular segment branches•Operculofrontal artery•M4- Cortical branches•Lat Orbitofrontal•Pre rolandic•Rolandic•Ant. parietal•Post. parietal•Angular •Temporopolar•Ant temporal•Middle temporal•Post. temporal

MCA supplyCortical branchesFrontal branches supply the precentral, middle and inferior frontal gyri.

Two parietal branches are distributed to the postcentral gyrus, the lower part of the superior parietal lobule and the whole inferior parietal lobule.

Two or three temporal branches supply the lateral surface of the temporal lobe.

-motor and somatosensory cortices, with the exception of the lower limb, the auditory area and the insula.

the lateral striate or lenticulostriate arteries - the lentiform complex and the internal capsule and the caudate nucleus

Posterior cerebral artery

• P1 or Peduncular segment• short segment from the basilar tip to the PComA

– Mesencephalic br. – Cr. Nv. Nuclei 3 - 6– Thalamoperforating arteries - diencephalon and midbrain

• P2 or ambient segment• runs in the ambient cistern from the PComA to the portion of paramesencephalic cistern

– Thalamogeniculate br.– Medial posterior choroidal arteries– Lateral posterior choroidal arteries– Ant temporal

• P3 or quadrigeminal segment• Runs in calcrine fissure

– Hippocampal artery– middle, and posterior temporal arteries– Posterior pericallosal arteryP4 –DISTAL SEGMENT– Parieto-occipital artery– Calcarine artery

• The artery of Percheron is a rare variant of the posterior cerebral circulation characterised by a solitary arterial trunk that supplies blood to the paramedian thalamiand the rostral midbrain bilaterally.

POSTERIOR CEREBRAL ARTERY SUPPLIES The cortical branches.Temporal branches-to the uncus and the parahippocampal, medial

and lateral occipitotemporal gyri. Occipital branches- the cuneus, lingual gyrus and posterolateral

surface of the occipital lobe. Parieto-occipital branches -cuneus and precuneus.-the visual areas of the cerebral cortex and other structures in the

visual pathway. The central branches the anterior thalamus, subthalamus, globus pallidus and lateral

geniculate body .the choroid plexus of the third and lateral ventricles and the fornix.supply the peduncle and the posterior thalamus, superior andinferior colliculi, pineal gland and medial geniculate body.

Blood supply of internal capsule

• Striate branches of anterior cerebral artery. (recurrent artery of Huebner). -genu and anterior limb

• Medial and lateral striate branches of the middle cerebral artery. (Charcot‘s artery of cerebral haemorrhage). -the posterior limb of the internal capsule.

• Central branches of the anterior choroidal artery -sublentiform part.

• Some direct branches from the internal carotid artery -genu.

• Central branches of the posterior communicating artery.

• Posterolateral central branches of the posterior cerebral artery -retrolentiform and sublentiform parts

Mid brain blood supply

• Most of the blood supply is derived from branches of the basilar artery.

• Posterior cerebral• Superior cerebellar• Posterior communicating• posterior choroidal

Pons blood supply

The pons is supplied by the following arteries:• Numerous (pontine) branches from the basilar

artery.• Superior cerebellar artery.

Medulla blood supply

• The medulla is supplied by the following arteries:

• Two vertebral arteries.• Anterior and posterior spinal arteries.• Anterior and posterior inferior cerebellar

arteries.• Basilar artery

• Branches of the vertebrobasilar

system and of the internal carotid

artery and P2 segment of the

posterior cerebral artery

• Lateral choroidal arteries -the

lateral and third ventricles.

• Posterior inferior cerebellar

arteries - choroid plexus in the

fourth ventricle .

• Anterior inferior cerebellar

arteries- choroid plexus of the

foramen of Luschka

BLOOD SUPPLY OF VENTRICLES

Venous Drainage of The Brain

features-does not follow the arterial pattern.

- thin-walled due to absence of muscular tissue in their walls.

-no valves.

-runs in the subarachnoid space.-superficial and deep

sinuses of the dura mater (1) a postero-superior at the upper and back part

of the skull. 1 Superior Sagittal2 Straight sinus3 Inferior Sagittal4 Two Transverse. 5 Occipital

(2) an antero-inferior at the base of the skull. 1 Two Cavernous2 Two Superior Petrosal3 Two Intercavernous 4 Two Inferior Petrosal5 Two sphenoparietal

• Thalamostriate vein +

Choroidal vein+Septal

= Internal cerebral vein

• Internal cerebral vein +

Basal Vein of Rosenthal

= Great vein of Galen

• Great vein of Galen +

ISS = Straight sinus

• Superior cerebral vein drain to SSS

• SSS connects to superficial middle cerebral vein by Troland’s vein.

• Transverse sinus to superficial middle cerebral vein by vein of Labbe’.

• SSS + straight sinus + Occipital sinus = Transverse sinus

• Transverse sinus later drain into sigmoid sinus and then to IJV.

• Inferior cerebral vein drain to superficial middle cerebral vein terminates to cavernous sinus

• Transverse sinus to superficial middle cerebral vein by vein of Labbe’.

• Anterior cerebral vein + Deep middle cerebral Vein + Striate veins = Basal Vein of Rosenthal

• Cavernous sinus drain to transverse/sigmoid sinus via superior and inferior petrosal sinus.

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