Blood Supply of the Brain

Blood Supply of the Brain

its survival and functioning depend on continuously receiving: 20% of the arterial blood flow from the heart, metabolizing 20% of the available oxygen, and generating 20% of the bodily energy.

* Vertebral Arteries
* Internal Carotid Arteries

the two pair of trunk arteries where the arterial blood supply of the brain is derived.

Vertebral Arteries

enters the vertebral foramen to supply parts of the brain.

Internal Carotid Arteries

emerged from the bifurcation of the common carotid artery to supply the brain.

External Carotid Arteries

another bifurcation of the common carotid artery that supplies the face.

Vertebral Circulation

\- originated from the main branches coming from the aorta (subclavian artery)

\- paired vertebral arteries enters the cranial cavity through the foramen magnum to unites at the midline at the pontomedullary junction to form the basilar artery, then it continues to the midbrain level, where it bifurcates to form the paired posterior cerebral arteries

Verterbal Artery

\- branch of the 1st part of the subclavian artery

\- ascends the neck through the transverse foramina of the upper 6 cervical vertebrae to enter the skull through the foramen magnum

\- Meningeal Arteries

\- Anterior and Posterior Spinal Arteries

\- Posterioinferior Cerebellar Artery

\- Medullary Arteries

branches of the vertebral artery.

Meningeal Arteries

\- small branches of arteries that supply the cranial meninges; supplies the bone itself and the dura mater of the cranial fossa of the skull

\- are perforating

Anterior Spinal Artery

\- descend as 1 artery (unite left and right anterior spinal artery to supply the anterior 2/3 of the spinal cord

\- also supplies the meninges like pia mater

\- has many radicular artery

Posterior Spinal Artery

\- arise at the start of the vertebral artery as it enters the foramen magnum

\- supplies the posterior 1/3 of the spinal cord

\- paired (left and right)

Posteroinferior Cerebellar Artery

\- largest branch of the vertebral artery and supplies:

* vermis
* central nuclei of the cerebellum
* inferior portion of the cerebellar hemisphere
* dorsolateral portion of the rostral medulla
* choroid plexus of the 4th ventricle

Medullary Arteries

branch of the vertebral artery that supplies most of the medulla, along with the postero-inferior cerebellar artery.

Basilar Artery

\- formed by the union of the vertebral artery at the level of the pontomedullary junction

\- branches to pons, cerebellum, and internal ear

Labyrinthine Artery

\- follows the course of CN VII and VIII to supply the inner ear

\- very narrow

* Facial Nerve
* Vestibulocochlear Nerve
* Labyrinthe Artery

three structures that enter the internal auditory meatus.

Anterior Inferior Cerebellar Artery

\- supplies part of the pons and the anterior and inferior regions of the cerebellum

\- pass laterally and posteriorly to supply the anterior and inferior portion of the cerebellum along with the postero-inferior cerebellar artery

\- radicular branches:

* *superior medulla oblongata*
* *anterior portion of cerebellum*
* *inferior portion of cerebellum*

Superior Cerebellar Artery

\- supplies part of the rostral pons and superior regions of the cerebellum

\- minute branch also supplies the rostral portion of pons

Pontine Branches

\- supply most of the pons

\- perforating artery that winds around the brainstem

Posterior Cerebral Artery

- located laterally and backward around the midbrain and is joined by the posterior communicating branch of the internal carotid artery to form the circle of willis

- most important part of basilar artery; marks the end of it

- has three branches:

• cortical branches

• central branches

• choroidal branches

Cortical Branches of PCA

\- supplies the inferior, lateral, and medial portion of the temporal lobe

\- supplies the lateral, medial, and inferior portion of both occipital lobes

Central Branches of PCA

supplies the thalamus and part of the lentiform nucleus including the pineal and medial geniculate body.

Choroidal Branches of PCA

\- supplies the inferior portion of the choroid plexus within the lateral ventricle

\- also supplies part of the choroid plexus of the third ventricle

* Opthalmic Artery
* Posterior Communicating Artery
* Anterior Choroidal Artery
* Anterior Cerebral Artery
* Middle Cerebral Artery

branches of the internal carotid artery.

Anterior Cerebral Artery

\- supplies the orbital and medial aspect of the frontal lobe and medial aspect of parietal lobe

\- smaller than MCA and runs forward in the medial portion to the top of the optic nerve

\- curves backward to supply the rest of the medial portion of the cerebral cortex and communicates with the PCA

Anterior Communicating Artery

artery that communicates the right and left ACA.

Cortical Branches of ACA

\- supplies the medial surface of the cerebral cortex as far as the patieto-occipital area of the brain

\- also supplies a strip of the cerebral cortex on the medial surface

Central Branches of ACA

penetrating and perforating branches of these supplies the basal ganglia:

* *lentiform nucleus*
* *caudate nucleus*
* *anterior limb of the internal capsule*

Recurrent Artery of Heubner

\- branch of the ACA that supplies the central portion of the brain

\- perforating artery that supplies the basal ganglia:

* *lentiform nucleus*
* *caudate nucleus*
* *anterior limb of the internal capsule*

Medial Cerebral Artery

\- largest branch of the internal carotid artery

\- runs laterally supplying the lateral surface of the brain, and comes out of the lateral sulcus

\- supplies the orbital gyrus, and the frontal, parietal, and temporal lobes on the lateral portion

Cortical Branches of MCA

supplies the entire lateral portion of the cerebral hemisphere.

Central Branches of MCA

supplies the basal ganglia

*- lentiform nucleus*

*- caudate nucleus*

*- genu of the internal capsule*

Lenticulostriate Artery

\- pentrating branches of MCA

\- most important penetrating vessels of the brain because of the area it supplies (subcortical area)

Lacunar Infarction

narrowing of the lenticulostriate artery that leads to decrease blood supply on the internal portion of the brain.

Ophthalmic Artery

\- supplies the eye and other orbital structures, and its terminal branches supply the frontal area of the scalp, ethmoid, frontal sinuses, and dorsum of the nose

\- first branch of the internal carotid artery

Amaurosis Fugax

\- monocular blindness

\- injury to the ophthalmic artery may lead to this

* Amaurosis Fugax
* Aphasia

unique characteristics of an anterior circulation stroke or internal carotid stroke.

Posterior Communicating Artery

\- artery that communicates internal carotid artery and PCA

\- runs posteriorly above the oculomotor nerve to join the posterior cerebral artery, thus forming the circle of willis

Anterior Choroidal Artery

\- passes posteriorly close to the optic tract, enters the inferior horn of the lateral ventricle, and end in the choroid plexus

\- supplies:

* *anterior portion of the lateral ventricle*
* *lateral geniculate nuclei*
* *optic tract*
* *posterior limb of internal capsule*
* *crus cerebri*

Circle of Willis

anastomotic connections so that occlusion need not to result in impairment of blood supply to the neural tissues.

* Anterior Communicating Artery
* Anterior Cerebral Artery
* Internal Carotid Artery
* Posterior Communicating Artery
* Posterior Cerebral Artery

components of the circle of Willis.