Cerebrovascular Anatomy

Naresh Mullaguri MD

Neurology Resident Physician PGY4

University of Missouri-Columbia

Cerebral Circulation Math

Cerebral Blood Flow and Brain Death

Embryology of Great cerebral Blood vessels

Variations in the Origin of the Great cerebral vessels

Branches of the Common carotid artery

1. Paired arteries

2. Right side takes origin from

the Brachiocephalic trunk at

the level of Sternoclavicular

joint

3. Left side takes origin from the

arch of Aorta in the superior

mediastinum at the level of

second intercostal joint

External Carotid Artery Branches

Branches of the External Carotid Artery

Who don’t like Mnemonics

Ophthalmic Artery

1. Originates at the level of Anterior

Clinoid process of the ICA. So it is

intradural at the site of origin,

2. It supplies the contents of the orbit,

Sphenoid sinus, Ethmoid air cells,

Nasal mucosa, Dura mater of the

Anterior Cranial Fossa, Skin of the

Forehead, Root of the nose and

Eyelids.

3. In case of stenosis of the ICA, the

cutaneous branches of the Ophthalmic

artery forms anastomosis with the

branches of the ECA.

PCOM1. In the early stages of the embryonic

development, it is a proximal segment of

the Posterior Cerebral Artery which is at

first a branch of the ICA and only later

comes to be supplied by the Basilar

Artery.

2. Fetal origin of the PCOM - 25%

3. Joins the PCA at 10mm lateral to the

Basilar tip.

4. Most important anastomotic connection

between the Anterior and Posterior

circulation

5. Perforating branches to Tubercinerium,

mamillary body, Rostral thalamic nuclei,

Subthalamus and part of Internal Capsule

Arterial Supply of the Interior of the Brain

1. Anterior Choroidal Artery: Branch of ICA distal to the

PCOM runs towards the occiput parallel to the Optic

tract and then enters Choroidal fissure to supply the

choroid plexus of the Temporal horn of the Lateral

ventricle.

2. It gives branches to Optic tract, Uncus, Hippocampus,

Amygdala, Part of the Basal ganglia, Part of the

Internal capsule. It also supplies part of fhe Pyramidal

tract.

3. Anastomotic connections with the Lateral posteriro

Choroidal Artery.

CEREBRAL ARTERIAL

TERRITORIES

Middle Cerebral Artery

Anteiror Cerebral Artery

Posterior Cerebral Artery

Anterior Choroidal Artery

Posterior inferior Cerebellar

Artery

Superior Cerebellar Artery

Lenticulostriate Arteries

The proximal section of the Anterior Cerebral Artery gives off Perforating branches

to the Paraseptal region, Rostral portion of the Basal Ganglia, the diencephalon,

Anteior limb of the Internal Capsule

RECURRENT ARTERY OF HEUBNER

It is the large branch of Anterior Cerebral

Artery that supplies the Basal Ganglia

sometimes visible on the angiogram. It is the

distal part of the medial Striate artery.

Supplies the Anterior-medial section of the

Caudate nucleus, Anterior-inferior section of

the Internal Capsule as well as parts of the

putamen and Septal nuclei

ACOM Aneurysm Rupture

Cotical Branches of the Middle Cerebral Artery

1. Orbitofrontal

2. Prerolandic

3. Rolandic

4. Anterior Parietal

5. Posterior Parietal

6. Artery of Angular gyrus

7. Temporo-occipital/Posterior

Temporal

The cortical areas

supplied by the MCA

include Language

areas of Broca and

Wernicke, the Primary

auditory cortex and

gustatory cortex.

ARTERIES OF THE POSTERIOR FOSSA

Vascular Anatomy in this region is highly

variable

Anterior Spinal Artery always arises from

the Intradural portion of the Vertebral Artery

Vertebral Artery

POSTERIOR INFERIOR CEREBELLAR ARTERY

Largest branch of Vertebral Artery

Supplies the basal portion of the

cerebellar hemispheres, The lower portion

of the Vermis, part of the cerebellar nuclei

and the choroid plexus of the IV ventricle

and Dorsolateral portion of the Medulla

Congenitally small vertebral artery may

terminate as PICA and give off no

contribution to the Basilar artery, which in

such cases is simply a continuation of the

contralateral vertebral artery

BASILAR ARTERY

Arises from the union of Right and Left Vertebral arteries in front of the Brainstem

at a lower pontine level

Branches: 2 pairs of cerebellar arteries (AICA and SCA) and the Posterior

Cerebral arteries

Small perforating branches to Brainstem

Paramedian branches, short and long circumferential branches.

ANTERIOR INFERIOR CEREBELLAR ARTERY

First major branch of the Basilar artery

Supplies the Flocculus, Anterior portion of the Cerebellar hemisphere

Anastomoses with branches of PICA and its distribution is highly variable.

Gives of Labyrinthine artery to the inner ear

SUPERIOR CEREBELLAR ARTERY

Arises from the basilar artery below its

tip and supplies the Rostral portion of

cerebellar hemisphere and upper

portion of the vermis

As it curves around the midbrain, it

gives off branches to the midbrain

POSTERIOR CEREBRAL ARTERY

At an earlier stage in the ontogenic

development, the PCA is a branch of ICA

It originates at the Basilar bifurcation and

then curves around the midbrain and

enters the AMBIENT cistern where it has a

close spatial relation to the tentorial edge

Within the cistern, the PCA divides into

major cortical branches including

Calcarine, Occipito-temporal arteries and

Temporal Branches

Thalamoperforating Branches

Anteior and Posterior arteries

Anterior TPA/Thalamotuberal artery:

Mainly supplies the Rostral portion of

the Thalamus

Posteior TPA/Thalamoperforating

Artery: Basal and medial portions of

the Thalamus as well as the Pulvinar,

Sometimes share a common trunk

called the Artery of Percheron

Thalamogeniculate Artery

DIstal to the origin of the PCOM

It supplies the lateral portion of the Thalamus

Posterior Choroidal Arteries

Medial Branch : Supplies the midbrain and also the choroid plexus of the III

ventricle

Lateral Branch supplies the choroid plexus of the Lateral ventricle and has an

anastomotic connection with the anterior choroidal artery.

Both arteries supply the Geniculate bodies, Medial and posteromedial thalamic

nuclei and the Pulvinar

CORTICAL BRANCHES OF THE PCA

PCA territory is delimited by the Sylvian fissure. In others the MCA supplies the

entire convexity of the Brain including the Occipital pole.

The visual cortex of the calcarine sulcus is always supplied by the PCA. The optic

radiation is however often supplied by the MCA so that homonymous hemianopsia

doesn’t always incline an infarct in the territory of the PCA

The PCA also has temporal branches to the temporal lobes

COLLATERAL

CIRCULATION OF

THE BRAIN

COLLATERALS FROM EXTERNAL TO

INTERNAL CAROTID CIRCULATION

1.External carotid artery - Facial Artery -

Angular Artery - ICA

2.ECA - Superficial temporal artery - Angular

Artery - ICA

COLLATERALS FROM EXTERNAL TO

VERTEBRAL CIRCULATION

1. ECA-Occipital Artery-Vertebral Artery

CIRCLE OF WILLIS

LEPTOMENIGEAL COLLATERALS

CALLOSAL ANASTOMOSIS

Unlike the rest of the body Veins don’t run together with its arterial counterparts.

The territories of the Cerebral arteries do not coincide with the cerebral veins

Venous blood from Brain parenchyma crosses the subarachnoid and subdural

spaces in short cortical veins like Superior anastomotic vein of Trolard, Dorsal

superior Cerebral Vein, Superficial middle cerebral vein and Inferior Anastomotic

vein of Labbe.

VENOUS ANATOMY

Superolateral and Sagittal sections showing Cerebral veins

Deep Cerebral Veins

● Venous blood from the deep regions of the

Brain including the Basal ganglia and thalamus

drain into the paired Internal Cerebral veins and

paired Basal Veins of Rosenthal

● Internal Cerebral veins are created by the

confluence of the Septum Pellucidum with the

Thalamostriate vein

● These 4 veins from both sides join behind the

Splenium to form the Great Vein of Galen

● The Blood from there is drained into the

Straight sinus (Sinus Rectus) and then into the

confluence of sinuses (Confluence sinus,

torcular herophili)

Dural Sinuses

● Superficial and deep veins of the Brain drain

into the Dural Venous sinuses.

● Most of the venous drainage in the Superior

Sagittal sinus travel from front to back which

runs in the midline along the attachment of Falx

Cerebri

● At the point in the back of the Head where the

Falx cerebri merges with the Tentorium, the

SSS is joined by the Straight sinus which runs

in the midline along the attachment of tentorium

and carries blood from deep regions of the

Brain.

● The blood from the SSS and SS is then

distributed to two Transverse Sinuses in the

Dural Sinuses Contd...

● From the TS the blood drains into the

Sigmoid sinuses and then to the

Internal Jugular vein.

● The sinuses are often asymmetric and

a number of variants of the venous

drainage patterns.

Pterygoid Plexus

● Blood from the brain also drains into

the viscerocranial system by the way

of Pterygoid plexus.

● The cavernous sinus formed by the

dural folds at the base of the Skull

also drains from basal regions of the

Brain; from the temporal lobes and

from Orbit by way of Superior and

Inferior Ophthalmic veins.

● It is connected to the Sigmoid sinus

through Superior and Inferior Petrosal

sinuses

Cerebral Venous Drainage

Cortical Veins => Superior Sagittal Sinus

Sphenoparietal sinus => Cavernous Sinus

Vein of Labbe => Transverse Sinus

Internal Cerebral Veins => Straight Sinus

VASCULAR ANATOMY OF SPINAL CORD

Mostly anastomotic blood supply from Anterior Spinal Artery and paired Posterior

Spinal arteries

Anterior Spinal Artery:

● It runs down the ventral surface of the Spinal cord at the anterior edge of the

anterior median fissure. It receives Segmental contribution from a number of

arteries and supply to the ventral part of the spinal grey matter through

perforating vessels known as SULCO-COMMISSURAL ARTERIES.

● Each artery supplies one half of the spinal cord, important structures supplied

by the ASA include Anterior Horns, Lateral Spinothalamic tract and part of the

Pyramidal tract.

POSTEROLATERAL SPINAL ARTERIES

● Paired

● Runs on the Dorsal side between the Posterior roots and lateral columns on

either side.

● Supplies the posterior columns, roots and Dorsal horns

● The longitudinal axis are connected by radicular anastomosis. These

arteries supply the anterior and Lateral columns through perforating

branches.

● In the periphery however, the arteries of the spinal cord are functional end

arteries. Intramedullary embolic occlusion of a Sulco-commissural artery

therefore causes infarction of the Spinal cord.

ARTERIAL NETWORK OF SPINAL CORD

● Number of segmental arteries contribute

to the blood supply of Spinal cord

● In the Upper Cervical Region, the

anterior spinal artery receives most of

the blood from the Vertebral artery

● Further down the cord, Longitudinal

vessels receive blood from the Vertebral

artery, subclavian artery or both.

● Segmental arteries preferentially arise

from the Costocervical and

Thyrocervical trunk.

● From T3 down, the ASA is fed by the

Aortic branches

● The thoracic and Lumbar segmental

arteries also contribute few branches to

ASA or the posterolateral Spinal

Arteries.

● Segmental artery is divided into Anterior

and Posterior branches which enter the

Spinal Canal with the anterior and

Posterior root

GREAT RADICULAR ARTERY OR ARTERY OF

ADAMKEIWICZ

Large segmental artery supplying the lower Spinal cord

T9-L1

THe developmental ascent of the Spinal cord makes this

artery join the ASA at an acute angle (Hairpin

configuration)

VENOUS DRAINAGE OF SPINAL CORD

● EPI-MEDULLARY VENOUS NETWORK

Also called Internal Spinal venous plexus -

Drains the spinal cord into the Subarachnoid

area. These communicate with the radicular

vein with the epidural venous plexus.

● EPIDURAL VENOUS PLEXUS

Anterior and Posterior External Vertebral

venous plexus

Drains into the large veins of the Body.