1. brain vascularisation 2014 dr. an an, m.sc., sp

8/10/2019 1. Brain Vascularisation 2014 Dr. an an, M.sc., Sp

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CEREBRAL VASCULARIZATION

DANAPLIKASI KLINIS NEUROLOGI


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Arterial Blood Supply of the Brain

Derived from:

- Internal carotid artery:

to anterior 2/3 of the cerebral hemispheres

- Vertebral artery:

to the remaining posterior and medial regions of

the hemispheres, most of the diencephalon, brainstem,

cerebellum, and cervical spinal cord.

Arteries of the brain lie in the subarachnoid space


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Anatomi


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Anastomosis

The carotid and vertebral-basilar are anatomically

interconnected with each other, and with their

counterparts in the opposite site, through the circle of

Willis.

These circle usually cannot carry enough blood flow

to maintain adequate cerebral circulation if either a

carotid or a vertebral artery is suddenly blocked.


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Circulus arteriosus Willis

1. Basilar

2. Posterior cerebral

3. Posterior communicating

4. Internal carotid

5. Anterior cerebral6. Anterior communicating
http://www.bartleby.com/107/illus516.html


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Anatomi


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Branches of Internal Carotid Artery cavernous part

- cavernous

- hypophyseal

- meningeal

cerebral part

- ophthalmic

- anterior cerebral

- middle cerebral- anterior choroid

to: globus pallidus, caudate

nucleus, amygdala,

hypothalamus, red nucleus,

substansia nigra, capsula interna(post. limb), optic radiation,

hippocampus.

- posterior communicating


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Anatomi


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Internal carotid artery in the cavernous sinus
http://www.bartleby.com/107/171.html


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Anterior Cerebral Artery

Areas supplied by anterior cerebral artery: Septal area

Primary motor cortex for legs, foots, urinary bladder

Additional motor planning areas in the medial frontal lobe anterior

to precentral gyrus Most of the corpus callosum except its posterior part


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Middle Cerebral Artery

Central branches: Lenticulostriate artery

Through: anterior perforate substance

To: lentiform nucleus, caudate nucleus and internal capsule

Cortical branches:

Superior branch to:

Primary motor cortex for face and arm Brocas area

Frontal eye fields (for looking at eye movements to theopposite site)

Primary somatosensory cortex for face & arm Parts of lateral frontal & parietal lobe for 3-D visual

perceptions and for ability to interpret & express emotion


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Cortical branches (cont.)

Inferior branches to

Wernicks area

Parts of posterior parietal lobe for 3-D visualperceptions and for ability to interpret & express

emotion

Optic radiation particularly fibers that representinformation from the contralateral superior

quadrants of the visual field


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Anatomi


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Outer surface of hemispherium showing areas

supplied by cerebral arteries


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Medial surface


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Branches of Vertebral & Basilar arteries

Vertebral:

- posterior & anterior spinal

- posterior inferior cerebellar

Basilar:- pontine

- labyrinthine

- anterior inferior cerebellar- superior cerebellar

- posterior cerebral

- posterior communicating


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Areas supplied by vertebral-basilar

arteries

Rostral midbrain:

- Pyramidal tract (PT), superior cerebellar peduncle,

n. III nucleus, medial longitudinal fasciculus (MLF),reticular formation (RF)

Mid pons:- MLF, RF, PT, middle cerebellar peduncle (MCP),

trigeminal sensory & motor nuclei


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Areas supplied by vertebral-basilar arteries

(cont.)

Caudal pons:- n. VI nucleus, motor fibers n. VII, lateral gaze center, PT

- n. VII nucleus, MCP, descending tract nucleus n. V,spinothalamic tract (ST), vestibular & cochlear nuclei

Rostral medulla:

-n. XII nucleus, PT, medial lemniscus

- nucleus ambiguus, n. IX & X, descending tract nucleus n.V, ST, Vestibular nuclei, Inferior cerebellar peduncle


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Structures supplied by posterior

cerebral artery

- Diencephalon

- Midbrain

- Optic radiation & striate cortex (primary visual

cortex)

- Splenium of the corpus callosum

- Hippocampal formation & the posterior of fornix

(important for new declarative memory)


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Cerebral Blood flow

Every minute, -

50 ml/100 g/min

- about 600-700 ml of blood flow throughthe carotid arteries and their branches

- about 100-200 ml flow through the

vertebral-basilar system.


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Cerebral Blood flow

Cerebral blood flow constant despite variation in bloodpressure (65-140 mm Hg).

Below this range cbf decrease

Above cbf increase

Control by sympathetic insubarachnoid space and byadrenegic intrinsic inside the brain

CO2 and O2 also important

Intracranial pressure & cbf complex autoreg


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Blood-Brain Barrier

Located at capillary endothel within brain, exceptcircumventric. system

Depends on the tight junction between endothel and a

relative lack of transport

Function

Protect brain from circulating substanceSelective transport of substances by specialized transport

system

Metabolism & modification of blood or brain borne substance


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Atheromatous plaques

Atheromatous plaques tend to form at branchings and

curves of the cerebral arteries.

In the carotid circulation the most frequent sites:

- in the internal carotid artery at its origin

- in the stem MCA or its bifurcation into superior

and inferior divisions- in the ACA as it curves backwards over the corpus

callosum.


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Emboli

Emboli tend to enter the carotid circulation far morefrequently than they enter the vertebral circulation

Large emboli carried up the carotid tend to be swept into

the MCA --> prone to getting stuck at its branches in the

Sylvian fissure

Emboli can also lodge in one of the major corticalbranches of MCA as well as in the smaller branches


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Lenticulostriate arteries

Small diameter arteries originate as right angle branches ofMCA.

Particularly susceptible to damage from hypertension.

Rupture of the artery produces an intracerebral hemorrhage,initially centered in the region they supply

Occlusion produces a lacunar infarct.

--> leads to stereotyped stroke syndromes.


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Lenticulostriate arteries

Hemorrhage:

- may remain localized to the putamen (and caudate)

- may involve neighboring structures (internal caps.etc)

- may rupture into ventricular system

Lacunar infarct:

- may have serious functional consequences if they involveinternal capsule

- may silent if they involve small region of white matter orbasal ganglia.


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Stroke lakunar


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Stroke infark

-

ApoptoticCell Death

NecroticCell Death

IschemicInjury


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Stroke infark


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Stroke infark


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Stroke


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Penetrating cerebellar vessels are also at risk forhypertensive hemorrhage, with bleeding often occuring

near the dentate nucleus--> deficits related to the cerebellum such as limb ataxia.

It may also affect brainstem function by compression or by

rupture into the fourth ventricle


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APLIKASI KLINIS


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Largest branch of InternalCarotid.

Supplies portion of frontal lobe

and lateral surface of Temporal

and Parietal lobes.

Primary Motor and Sensory

areas for face, throat , hand and

arm.

Dominant hemisphere, supplies

area controlling speech.

Is the Artery most often occluded

in stroke.

Middl C b l A t


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Middle Cerebral Artery The MCA proceeds laterally into the lateral

sulcus and spreads to supply virtually the entirelateral surface of the cerebral hemiphere, where

most of the precentral and postcentral gyri are

located.

Included in this region are the motor speech of

area Broca and the sensory language area of

Wernickle.

MCA also supply the putamen, part of the

caudate nucleus, the outer globus pallidus, the

posterior limb of the internal capsule and the

corona radiata.


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Characterized by weakness of the contralateralface with hemianopsia and a preference of theeyes and head toward the side of the involved

hemispere Aphasia in dominant hemisphere injury

Hemineglect

Involvement restricted to branches of the MCAmay produces fragment of this syndrome sparingof leg strengh


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Middle Cerebral Arterysuperior

division Weakness - upper and lower extremity (C)

Weakness - face - lower half (C)

Hemisensory loss - upper and lower extremity

(C)

Sensory loss - face - all modalities (C)

Hemineglect (ND)

Aphasia expressive (D)

(AHA Stroke Center, 2004)


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Visual loss - homonymous hemianopia (C)

Visual loss - upper quadrant anopsia (C)

Constructional apraxia (ND)

Aphasia receptive (D)

Middle Cerebral Arteryinferior division

( AHA Stroke center, 2004)


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The ACA follow the corpus callosum supplying

the anterior four fifths of the corpus callosum and

medial aspect of the frontal and parietal lobes.Deep branches, arising near the circle of Willis,

supply the anterior limb of the internal capsule,

the inferior head of caudate nucleusand theanterior part of the globus pallidus.


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Much rarer

The classic presentation is proximal arm/leg

weakness with present of distal strength, the so-

called manin a barrel

ACA occlusions cause contralateral motor and

somatosensory deficits, primarily of the lower

extremities. In addition, apraxia, mental and personal

changes, primitiv reflexes and bowel and bladder

incontinence often ptresent


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Posterior Cerebral Artery


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Posterior Cerebral Artery

Involves the brainstem, cerebellum, thalamus &

occipital lobes

Present with bilateral limb weakness or sensory

disturbances, cranial nerve defisit, ataxia,

nausea, and vomiting or coma occlusion of the basilar artery trunk : Present with

hemianopia, memory disturbance, mild

personality disturbance Rarely; bilateral thalamus : a state of decreased

responsiveness and apathy without motor,

sensory or visual impairment


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Arterial Blood Supply of the spinal cord

1. Posterior & anterior spinal arteries

2. Spinal branches of vertebral, deep

cervical, intercostal and lumbar arteries

Blood supply of the


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Blood supply of themeninx

Blood Supply

anterior, middle & posterior meningeal

arteries

Blood supply to the cerebral hemisphere


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pp y p

Comes from cortical branches of the:

- ant.or

, middle & post.or

cerebral arteriesSubarachnoid vessels pass into subpial space --> enter

the cortex perpendicularly and divide: --> long &

short ramies

Long branches penetrate white matter 3-4 cm without

anastomosing --> terminal arteriesShort branches to cortex & makes anastomoses


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Dural venous sinuses

Blood-filled spaces situated between

layers of dura mater:

Superior & inferior, straight, transverse,

sigmoid, and occipital sinuses

- Confluens of sinuses

- Cavernous sinuses

- Superior and inferior petrosal sinuses


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A t i


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1. brain vascularisation 2014 dr. an an, m.sc., sp

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