CNS Blood SupplyBy Dr.Esmatullah Hamed

Neurology Resident-AKUH

June 2013

Anterior and posterior circulation

► Anterior circulation: common carotid and its ramifications including ICA, MCA and ACA

► Posterior Circulation: refers to the vertebral and basilar arteries and their branches.

Brain Blood Supply

Anterior Circulation

C1: Cervical segment - From the bifurcation to the carotid canal

Ophthalmic artery

Anterior Choroidal artery

Posterior communicating artery

Circle of Willis

► The circle of Willis is the joining area of several arteries at the bottom side of the brain

► 1, anterior circulation, which is composed the MCA, ACA, and the anterior communicating artery which connects the two anterior cerebral arteries.

► 2, the posterior circulation, which is composed of the posterior cerebral arteries

► 3, the posterior communicating artery, which connects the middle cerebral with the posterior cerebral arteries, and forming a true circle.

Circle of Willis

► Formed by these arteries: Internal carotid A. Posterior cerebral A. Posterior communicating A. Middle cerebral A. Anterior cerebral A. Anterior communicating A.

► Links the internal carotid and vertebral basilar arterial systems.

Middle Cerebral Artery

► The MCA, the largest cerebral artery, arises from the trifurcation of the internal carotid arteries of the Circle of Willis, and comprises of 4 parts: M1, M2, M3, and M4

MCA-M1

MCA-M2

MCA-M3,4

MCA Branches

Lat.Lenticulostriate arteries( penetrate the lentiform nucleus and give multiple branches to the anterior limb, genu and posterior limb of the internal capsule.

Orbitofrontal Anterior temporal

► 1- Superior division prefrontal Precentaral Central Postcentral Parietal

► 2- Inferior division Middle temporal Temporo-occipital Angular

Anterior Cerebral Artery

ACA Branches

► Medial striate atery(recurrent artery of Heubner) (supplies the lower part of the anterior limb and genu of the internal capsule).

► Orbitalfrontal branches

► Frontopolar artery

► Callosomarginal artery

► Pericallosal artery

Posterior Circulation

PCA

PCA Branches

► Posterior choroidal

► Long quadrigeminal

► Thalamogeniculate

► Mesencephalic

► 1-Medial Branches parieto-occipital Calcarine Callosal branch

► 2-lateral Bronch Anterior temporal Posterior temporal Occipitotemporal

► The brain stem receives its blood supply exclusively from the posterior circulation.

Blood Supply of the Brain Stem

Vascular supply of the medulla

► The medulla is supplied by the vertebral arteries and their branches. its blood supply further subdivided into two groups,

► paramedian bulbar arteries are penetrating branches mainly from the vertebral artery that supply the midline structures of the medulla. at the lower medulla branches from the anterior spinal artery also contribute to this paramedian zone.

► the lateral bulbar arteries are branches of the vertebral artery or the PICA which supply the lateral portion of the medulla.

Vascular supply of the Pons► The basilar artery is the principle

supplier of the Pons. It gives off three types of branches.

► Paramedian arteries supply the medial basal Pons, including the pontine nuclei, corticospinal fibers and medial lemniscus.

► The short circumferential arteries supply the lateral aspect of the Pons and the middle and superior cerebellar peduncles.

► The long circumferential arteries together with branches from the AICA and superior cerebellar artery supply the pontine tegmentum and the dorsolateral quadrant of the Pons.

Vascular supply of the midbrain

► Branches of the SCA, PCA, P com, and the anterior choroidal artery.

► Branches of these arteries can

be grouped into paramedian arteries, which supply the

midline structures, and the long and short circumferential arteries, which supply the dorsal and lateral midbrain.

Blood Supply of the Cerebellum

► The cerebellum receives its blood supply from the three cerebellar vessels:

► 1, posterior inferior cerebellar artery (PICA) off of the vertebrals. supplies posteroinferior surface of cerebellar hemisphere , ipsilateral part of inferior vermis,

and lateral medullary areas.

► 2, anterior inferior cerebellar artery (AICA) the first branch of the basilar. supplies part of the pons and the anterior inferior surface and underlying white matter of cerebellum

► 3, Superior cerebellar artery (SCA) the last brache off of the basilar. supplies part of the rostral pons and superior region of the cerebellum

Blood Supply of the Cerebellum

Venous Drainage of the Brain

Venous Drainage of the Brain

Spinal Cord Blood Supply

► The two Posterior Spinal Arteries arise from the vertebrals and supply the posterior 1/3 of the cord.

► The Anterior Spinal Artery, formed from a Y-shaped union of a branch from each vertebral artery and supplies the anterior 2/3 of the cord.

► The Radicular arteries enter every intervertebral foramen and supply the spinal nerve roots. The radiculospinal branches arise from the vertebral arteries and the aorta. Of these branches, the largest is the great anterior radicular artery of Adamkiewicz (radicularis magna), which supplies the lower thoracic and upper lumbar parts of the cord

Anterior and posterior radicular arteries are formarterial vasocorona

Anterior spinal arteries :supply 2/3 anterior aspect of spinal cord

Spinal Cord Blood Supply

Posterior spinal arteries : supply 1/3 posterior aspect of spinal cord

Spinal Cord Blood Supply

Arterial vasocorona

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