Download MBBS Anatomy PPT 52 Cerebrum Anatomy Notes

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A Different lobes and surfaces of Cerebral hemisphere

B. Blood supply of different regions of cerebral hemisphere

C Important sulci and gyri

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D Different functional areas located in cerebral hemisphere

E. Lesions and its effects

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2

Cerebrum

Largest part of the brain

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Heavily convoluted bilobed

structure

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4

Cerebral hemispheres

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General Appearance:
Separated by a deep midline sagittal

fissure ? longitudinal cerebral fissure

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In the depth of the fissure, the corpus

cal osum connects the hemispheres

across the midline

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Gyri ? the folds of the surface of

hemispheres

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Sulci ? the fissures separate the gyri

5

Surfaces of Cerebral Hemisphere

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Three surfaces:

Superolateral surface

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Inferior surface

Medial surface

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Borders

1 Superomedial border

2 Superciliary border and inferolateral border

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(Shows preoccipital notch)

3. Medial orbital border, hippocampal border or

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inferomedial border and medial occipital border

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Lobes of Cerebral Hemispheres

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Cerebral hemispheres are divided into

lobes by the central, parieto-occipital,

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lateral and calcarine sulci

Lobes are named according to the

cranial bones under which they lie

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Lobes are:
Frontal
Parietal
Temporal

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Occipital
8

Cerebral hemisphere
? the essential features can be

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1

summarized by stating that:-

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1. the frontal lobe lies in front of

the central sulcus (1) and above

2

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the lateral sulcus (2) .

3

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2. the parietal lobe is behind the

central sulcus and above the

lateral sulcus.

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3. the temporal lobe is below the

lateral sulcus

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4. the occipital lobe lies below and

P

behind the parieto-occipital

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F

sulcus (3) .

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O

T

Main sulci

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1

1. Central sulcus

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3

2. Lateral sulcus
3. Parito-occipital sulcus
4. Calcarine sulcus

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2

5. Cingulate sulcus
6. Cal sosal sulcus ( Sulcus

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of corpus cal osum )

7. Orbital sulcus
8. Parahippocampal sulcus

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9. Col ateral sulcus

5

10. Occipiti-temporal sulcus

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6

- First (6) can be seen in

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sagittal sections

- Last 4 seen only in axial

4

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sections

Main sulci

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7

1. Central sulcus
2. Lateral sulcus
3. Parito-occipital

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sulcus

4. Calcarine sulcus
5. Cingulate sulcus

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6. Cal sosal sulcus (

Sulcus of corpus

10

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8

cal osum )

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9

7. Orbital sulcus
8. Parahippocampal

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sulcus

9. Col ateral sulcus
10. Occipiti-temporal

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sulcus
1. Central sulcus 2. Lateral sulcus 3. Parito-occipital sulcus
4. Calcarine sulcus

5. Cingulate sulcus

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6. Cal sosal sulcus ( Sulcus of corpus cal osum )

1

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3

5 6

2

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4

2

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2. Parahippocampal sulcus
3. Col ateral sulcus
4. Occipiti-temporal sulcus

3

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4

Main gyri

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1

2

1. Precentral

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3

2. Postcentral

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3

4

3. Frontal (superior, middle & inferior)

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3

4. Parietal (superior & inferior) 5-

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5

5. Temporal (superior, middle &

inferior)

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5

6. Cal osal

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5

7. Medial frontal
8. Paracentral lobule
9. Precuneus

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7

8

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10. Cuneus

6

11. Lingual gyrus

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9

12. Orbital gyri
13. Gyrus rectus

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10

14. Parahippocampal
15. Occipitotemporal (medial & lateral)

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11

16. Uncus
Main gyri

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13

1. Precentral

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2. Postcentral

12

3. Frontal (superior, middle & inferior)

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4. Parietal (superior & inferior) 5-

5. Temporal (superior, middle &

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inferior)

6. Cal osal

16

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7. Medial frontal

8. Paracentral lobule

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15

15

9. Precuneus

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14

10. Cuneus

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11. Lingual gyrus

12. Orbital gyri

13. Gyrus rectus

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14. Parahippocampal

15. Occipitotemporal (medial & lateral)

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16. Uncus
1

1. Rectus gyrus
2. Uncus ( parahippocampus

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gyrus )

2

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3. Hippocampal gyrus

3

9

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Main sulci

Central sulcus

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Indents the superior medial border of the

hemisphere, 1 cm behind the mid-point

It runs downward, forward and toward the

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lateral sulcus across the lateral aspect of the

hemisphere

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The central sulcus is the only sulcus that

indents the superior medial border

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Main sulci (Cont'd)

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Lateral sulcus

Deep cleft on the inferior and lateral

surfaces of the cerebral hemisphere

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It consists of a short stem and three rami

- Anterior horizontal , anterior

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ascending and posterior

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Main sulci (Cont'd)

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Parieto-occipital sulcus:

Begins on the superior medial border of

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the hemisphere, about 5 cm anterior to

the occipital pole

It passes downward and anteriorly on the

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medial surface to meet the calcarine

sulcus

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Main sulci (Cont'd)

Calcarine Sulcus- Medial surface

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Insula/Island Of Reil
? portion of the cerebral cortex

folded deep within the lateral

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sulcus.

? Play a role in consciousness and

emotions

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? The cortical area overlying the

insula toward the lateral surface of

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the brain is the operculum

(meaning lid).

? The opercula are formed from

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parts of the enclosing frontal,

temporal, and parietal lobes.

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? Insulaa is surrounded by circular

sulcus ( arrow !! )

Superior surface

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of temporal

operculum

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presents

anterior and

posterior

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transverse

temporal gyri
Other Sulci and Gyri

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Superolateral su12rface

Frontal lobe ? anterior to central sulcus

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and superior to lateral sulcus

Superolateral surface of frontal lobe is

divided by three sulci into four gyri

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Precentral sulcus and gyrus

Superior and inferior frontal sulci

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Superior, middle and inferior frontal gyri

Anterior and ascending rami of lateral

sulcus divide inferior frontal gyrus into

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PARS ORBITALIS, PARS TRIANGULARIS PARS

OPERCULARIS

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13

15

Superolateral surface

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Parietal lobe ? POST

CENTRAL SULCUS AND

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GYRUS

o INTRAPARIETAL SULCUS

AND SUPERIOR AND

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INFERIOR PARIETAL LOBULE

Lateral

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sulcus


Superolateral surface

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o PARIETAL LOBE-Few sulci extend into inferior

parietal lobule and divided into

o SUPRAMARGINAL GYRUS AROUND LATERAL

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SULCUS

o ANGULAR GYRUS AROUND SUPERIOR

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TEMPORAL SULCUS

o ARCUS TEMPORO-OCCIPITALIS AROUND

INFERIOR TEMPORAL SULCUS

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14

Superolateral surface

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Temporal lobe ? inferior to lateral sulcus

Two sulci ? SUPERIOR AND INFERIOR

SULCUS

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Three gyri- SUPERIOR, MIDDLE AND

INFERIOR TEMPORAL GYRI
Superior surface of temporal operculum

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(Superior temporal gyrus)presents anterior and

posterior transverse temporal gyri. Anterior

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gyrus forming primary auditory area, also called
HESCHL'S GYRUS

Superolateral surface

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Occipital lobe ? small area behind the

parieto-occipital sulcus

LATERAL OCCIPITAL SULCUS

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LUNATE SULCUS
TRANSVERSE OCCIPITAL SULCUS


MEDIAL SURFACE

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CINGULATE SULCUS AND CINGULATE GYRUS

CALLOSAL SULCUS

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PARACENTRAL LOBULE(CORTICAL CENTRE OF

MICTURATION AND DEFECATION) AND MEDIAL FRONTAL

GYRUS

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CALCARINE SULCUS AND PARIETO-OCCIPITAL SULCUS

SUPRASPLENIAL SULCUS IN PRECUNEUS

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INFERIOR SURFACE

ORBITAL SURFACE- OLFACTORY SULCUS, GYRUS RECTUS

ORBITAL SULCUS AND ORBITAL GYRI

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TENTORIAL SURFACE- MEDIAL COLLATERAL SULCUS AND LATERAL OCCIPITO-TEMPORAL

SULCUS

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LINGUAL GYRUS ? BETWEEN COLLATERAL SULCUS AND CALCARINE SULCUS

LINGUAL GYRUS ANTERIORLY CONTINUE WITH PARAHIPPOCAMPAL GYRUS WHOSE

ANTERIOR END HOOK LIKE LIMITED BY RHINAL SULCUS- UNCUS

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MEDIAL AND LATERAL OCCIPITO- TEMPORAL GYRUS

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BLOOD SUPPLY- SUPEROLATERAL

SURFACE

MIDDLE CEREBRAL ARTERY EXCEPT

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STRIP ALONG SUPEROMEDIAL BORDER FROM FRONTAL

POLE TO PARIETO OCCIPITAL SULCUS BY ACA

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OCCIPITAL LOBE AND INFERIOF TEMPORAL GYRUS

EXCLUDING TEMPORAL POLE BY PCA

BLOOD SUPPLY- INFERIOR

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SURFACE

ACA- MEDIAL PART OF ORBITAL SURFACE

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MCA-LATERAL PART OF ORBITAL SURFACE AND

TEMPORAL POLE

PCA- TENTORIAL SURFACE

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BROADMANS AREAS AND

FUNCTIONAL AREAS OF CEREBRAL

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HEMISPHERE

Specific

Sulci/Fissures:

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Central Sulcus

Longitudinal

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Fissure

Sylvian/Latera

l Fissure

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Transverse Fissure

http://www.bioon.com/book/biology/whole/image/1/1

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http://www.dalbsoutss.eq.edu.au/Sheepbrains_Me/human_bra
Frontal Lobe - Cortical Regions

Primary Motor Cortex

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/Brodmann,s area 4

Precentral Gyrus ? it cntro

ls

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all voluntary movements of

the contralateral side of the

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body

Site where movements of

the various parts of the

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body are initiated

Recieves sensory input fro m

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cerebellum and thalamus

The body is represented

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upside down along the

precentral gyrus

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Investigation (Phineas Gage)

Primary Motor

Cortex/ Precentral

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Gyrus

Broca's Area

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Orbitofrontal

Cortex

Olfactory Bulb

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Regions

Modified from:
secondary motor area/6,8,44 and 45

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Precentral gyrus,sup,middle,inf frontal gyri
It programs the activity of the PMA
Stronger stimulation is required to produce

the same degree of movement

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Broca's Area ?44,45
Inf.frontal gyrus
Brings about the formation of words.
Located on Left Frontal Lobe

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Broca's Aphasia ? Results in the ability to

comprehend speech, but the decreased

motor ability (or inability) to speak and

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form words

Frontal eye field 8,
Middle frontal gyrus

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Voluntary eye movements towards

opposite side and the

accomodation pathway

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also controls eyelid movements

Prefrontal cortex9,10,11,12
Concerned with the makeup of the

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individual,s personality

Head rotation area

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Parietal Lobe - Cortical Regions

Primary sensorymotor Cortex

1,2,3(Postcentral Gyrus) ? Site involved with

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processing of tactile and proprioceptive

information.

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?Somatosensory Association Cortex -5,7 sup

parietal assists with the integration and

interpretation of sensations.

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?Primary Gustatory Cortex 43

?Inferior part of the post central gyrus? Primary site

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involved with the interpretation of the sensation of

Taste.
Primary

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Somatosensory

Cortex/ Postcentral

Gyrus

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Somatosensory

Association Cortex

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Primary Gustatory

Cortex

Modified from:

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http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg

Regions

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Occipital Lobe ? Cortical

Regions

Primary Visual Cortex ? This is the primary area of

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the brain responsible for Vision

?Visual Association Area ? Interprets

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information acquired through the

primary visual cortex.

Primary Visual

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Cortex

Visual Association

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Area

Modified from:

http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg

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Regions

Temporal Lobe ? Cortical

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Regions

Primary Auditory Cortex ?41,42 mostly

hidden in the lateral sulcus

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Responsible for hearing
Its anterior part recieves low freq sounds
Post part ?high freq sounds
Sec. Auditory Cortex 22

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Interpretation of sounds
Temporal Lobe ? Cortical

Regions

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?Primary Olfactory Cortex ? sense of smel

(Not visible on the superficial cortex)

?Wernicke's Area superior and middle

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temporal gyri

?Understanding of speech
- Wernicke's Aphasia ? Words and sentences are

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not clearly understood, and sentence formation

may be inhibited.

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Primary Auditory

Cortex

Wernike's Area

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Primary Olfactory

Cortex (Deep)
Conducted from Olfactory

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Bulb

Modified from:

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Regions

http://www.bioon.com/book/biology/whole/image/1/1-8.tif.jpg

dominant hemisphere

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95-left
Broca
90% right handed
BLOOD SUPPLY

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Anterior and middle cerebral artery

(internal carotid artery)

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Posterior cerebral artery (basilar artery)

Physiological information about brain

? Left hemisphere is dominant in Which hemisphere

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90% of the right handed and 64%

is dominant ?!

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of the left handed

? Righ hemisphere is dominant in

10% of righ handed and 20% of

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left handed

? In the remaining 16% of left

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handed both hemispheres are

dominant .

? Speech areas in brain usual y in

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the dominant hemisphere !! ( OF

CLINICAL IMPORTANT )

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Brodmann areas

Motor areas of cortex

? 1- primary motor area :-

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- MSI area ( precentral gyrus )

MSI

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- MSI area ( Anterior part of

MSI

paracentral lobule )

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? 2- secondary motor area

? Posterior parts of frontal

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gyri extending medial y
Primary motor area
? Broadmann area 4

? The area Msl is where movements

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of the various parts of the body

are initiated,

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MSI

? Afferent :- receives its main inputs

MSI

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from

the

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cerebel um

and

thalamus.

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? Efferent :- the corticonuclear and

corticospinal (pyramidal) tracts.

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? MSI area receives many fibres

from the basal nuclei and is

concerned

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with

postural

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mechanisms, but this area is not

yet clearly understood.

Motor homunculus

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? the body is represented upside

down along this cortex, although

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the face itself is represented the

right way up.

? The face lies lowest, then the

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hand (a very large area), then arm,

trunk and leg.

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? The leg and perineum areas

overlap the superior border and

extend down on the medial

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surface of the hemisphere

? Blood supply :-

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? 1- middle cerebral artery

? 2- anterior cerebral a. ( leg area )

Primary motor area

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? Lesions to this area produce

contralateral paralysis !!

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? Organs that supplied bilateral y

are the less affected ...

? CNs are supplied bilateral y ?!!

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Secondary motor area
? Or supplementary motor area
? Broadmann are 6
? Location :- Posterior parts of

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frontal gyri extending medial y

? The function of the secondary

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motor area:

? 1- To store programs of motor

activity

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resulted

from

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past

experience

? 2-

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Controls

sequence

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of

movements

? 3- Controls spatial & postural

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orientation movements.

? 4- Controls bimanual movements.
? Blood supply: Middle & anterior

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cerebral arteries
secondary motor area
? Lesions :-

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? Apraxia (inability to execute learned purposeful movements despite

having the desire and the physical capacity to perform them).

? There is no or little loss of strength

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Boca's area

? The motor (anterior) speech area

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(of Broca, areas 44 and 45) is

usual y situated in the inferior

frontal gyrus on the left side (in

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right-handed and in most left-

handed people), below and in

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front of the face area and centred

on the pars triangularis between

the anterior and ascending rami of

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the lateral fissure.

? Damage to it produces motor

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aphasia -- difficulty in finding the

right words, but not paralysis of

laryngeal musculature.

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? Blood supply :-

? Middle cerebral a.

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Wernicke's area

? The posterior speech area (of

Wernicke) is in the posterior parts of

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the superior and middle temporal gyri

and extends into the lower part of the

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parietal lobe.

- It is connected to the Broca's, visual &

auditory cortex

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? Function:

? To understand the written and spoken

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language

? Its integrity is necessary for the

understanding of speech.

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? Lesion ... Receptive dysphasia; the

patient responds by intact, but

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irrelevant speech!

? Blood supply:

? Middle cerebral artery

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Prefrontal cortex
? The prefrontal cortex is an

extensive area that lies anterior to

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the precentral

? The prefrontal area is concerned

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with

1. the makeup of the individual's

personality.

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2. regulator of the person's depth of

feeling.

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3. It also exerts its influence in

determining the initiative and

judgment of an individual.

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Prefrontal cortex

? Lesions :-

? It is now general y agreed that

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destruction of the prefrontal

? region does not produce any

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marked loss of intelligence

? Tumour or traumatic destruction

of the prefrontal cortex result in

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the person's losing initiative and

judgment.

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? Emotional changes that occur

include a tendency to euphoria.

? The patient no longer conforms to

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the accepted mode of social

behavior and becomes careless of

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dress and appearance.

? Bipolar disorders

? Schizophrenia

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Sensory areas

? 1- Primary somatosensory area
- The postcentral gyrus

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1

- Posterior part of l p

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o a

b r

u alce

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e ntral

2

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- Recieves primary from thalamus
- Sensations from the oral region,

pharynx, larynx & perineum are

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received bilateral y

? 2- Secondary ( or association )

somatosensory area.

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- Occupies the superior parietal

lobule

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Primary sensory area

? Sensory homunculus:
? The amount of the cortex for a

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particular part of the bod is

related

to

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its

functional

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importance

&

number

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of

receptors ( not to its size)

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? Blood supply:
- Middle cerebral artery
- Anterior cerebral artery (leg area)

Primary sensory area

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? Lesions :-

? Lesions

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of

the

primary

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somesthetic area of the cortex

result in contralateral sensory

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disturbances, which are most

severe in the distal parts of the

limbs. Crude painful, tactile,and

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thermal stimuli often return,but

this is believed to be due to the

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function of the thalamus.

? The patient remains unable to

judge

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? degrees of warmth, unable to

localize tactile stimuli accurately,

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and unable to judge weights of

objects.

? Loss of muscle tone may also be a

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symptom of lesions of the sensory

cortex.
Secondary somatosensory area

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? Function:
- Receive different sensory

modalities & relate them to past

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experience. e.g; object recognition

without vision.

- Lesions = asterognosis !!

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- Inable to identify things without

see them ...

Primary visual cortex

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? Broadmann area 17

? Functions:
- Receives fibers from the opposite

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field of vision

- It also excludes & modulates

unwanted images!

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? Blood supply:
- Posterior cerebral artery

? Lesions :-

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? Crossed homonymous hemianopia

Secondary visual cortex

? Brodmann area 18,19

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? Surrounded by the primary visual

cortex ...

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? Functions to relate the visual

information to past experiences

? Lesions produce ... Visual agnosia;

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loss of ability to recognize objects

seen in the opposite field of vision

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WHY don't we see everything upside-down?
? -Brain makes images 'easier' to see by:
? 1- Combining the two images of the two eyes (in corpus cal osum).
? 2- Make images right-side-up (in the visual cortex).

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? It does this because your brain is so USED to see things upside-down that

it eventual y adjusts to it (it's easier to flip the image than to try using

hands and legs with an upside-down world)

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? For the first days, babies see everything upside-down!
Primary auditory area

? Broadmann area 41,42

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? In the inferior wal of lateral sulcus

? Afferent: Principal y from the

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medial geniculate body

? Blood supply:

- Middle cerebral artery

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- Lesions

produce ...

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Partial

deafness in both ears with

inability to locate sound.

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- The greater loss being in the

opposite ear

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- (cochlear nuclei send 2nd order to

the olivary nucleus & nuclei of

trapezoid body bilateral y)

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Auditory pathway

? Explaning why greter loss of

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inability to hear on the

opposite site !!!

? Cochlear n. send fibers more

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to the other side than the

same side ...

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Secondary auditory area
? Broadmann area 22
? Lies posterior to the primary

auditory area

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? Function:
- To interpret sounds and associate

the auditory input with other

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sensory information.

? Blood supply:
? Middle cerebral artery

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? Lesions : auditory agnosia !!

The dominant angular gyrus

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? This part is often considered a

part of the Wernicke area

? Lesion here results in inability to

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read (alexia) or write (agraphia).
Aphasia

Sensory aphasia

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Alexia

Agraphia

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Motor aphasia

A lesion resulting in a nonfluent expressive

aphasia would most likely be found in the

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(A) temporal lobe

(B) parietal lobe

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(C) frontal lobe

(D) occipital lobe

Alexia without agraphia and aphasia would

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most likely result from occlusion of the

(A) left anterior cerebral artery

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(B) right anterior cerebral artery

(C) left middle cerebral artery

(D) left posterior cerebral artery

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(E) right posterior cerebral artery

A patient is asked to bisect a horizontal line

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through the middle, to draw the face of a clock,

and to copy a cross. The patient bisected the

horizontal line to the left of the midline,

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placed all of the numerals of the clock on the

right side, and did not complete the cross on

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the left side. The most likely lesion site for this

deficit is the

(A) left frontal lobe

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(B) right parietal lobe

(C) left parietal lobe

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(D) right temporal lobe

(E) left occipital lobe
Arterial supply to Brain
? Tissue of the brain ( paranchyme )

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al is supplied by two sources ...

? 1- branches of internal carotid

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1

ACA

MCA

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artery

? 2- branched of basilar artery

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2

ECA

ICA

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PCA

Basialr a.

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CCA

Vertebral a.

Vertebral a.

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aorta

Subcalvain a.

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Subcalvain a.

Branches of the vertebral a.

1. Posterior

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inferior

cerebel ar a.

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2. Anterior spinal a.

2

1

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Branches of the basilar a.

1. Anterior inferior cerebel ar a.
2. Superior cerebel ar a.

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3. Posterior cerebral a.

32

1

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Blood supply to Brain
Anterior cerebral artery

? leaves the internal carotid artery

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and passes forwards above the

optic nerve

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? It is connected to its fellow of the

opposite side by the anterior

communicating artery. It is

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distributed to the orbital surface of

the frontal lobe and to the whole

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of the medial surface of the

hemisphere above the corpus

cal osum as far back as the parieto-

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occipital sulcus

Anterior cerebral artery

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? The motor and sensory areas for the opposite leg, foot and perineum,

including the micturition and defecation centres, lie in its territory.

? Because of the anastomosis via the anterior communicating artery, it is

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usual y possible for one anterior cerebral to be supplied with blood from

the contralateral internal carotid.

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Anterior cerebral a. syndrome
1. Hemiparesis or hemiplegia contralateral y, involving primarily the lower

limbs and pelvic floor musculature

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2. Sensory deficits contralateral y, involving primarily the leg and perineum
3. Apraxia (due to branches to the supplementary motor area and corpus

cal osum)

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4. Disconnection syndrome (due to cal osal branches)
5. Anosmia (due to branches of the olfactory bulb and olfactory tract)
6. Urinary incontinence
7. Grasp reflex and or sucking reflex contralateral y (if circle of Wil is

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compromised)

Middle cerebral artery
? The middle cerebral artery is

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the largest and most direct

branch of the internal carotid

and therefore most subject to

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embolism.

? It passes deep into the lateral

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sulcus to supply the cortex of

the insula and overlying

opercula.

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? It reaches the lateral surface of

the hemisphere
Middle cerebral artery

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? by continuing in the lateral

sulcus, from which its branches

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emerge and ramify over an area

that fal s short of the borders of

the lateral surface by one gyrus

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or its equivalent breadth.

?
? In its area of cortical

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distribution lie the motor and

sensory areas for the opposite

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half of the body, excluding leg,

foot and perineum (which are in

anterior cerebral territory), and

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the auditory and speech areas.

Middle cerebral a. syndrome
1. Hemiparesis or hemiplegia of the lower half of the contralateral face

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2. Hemiparesis or hemiplegia of the contralateral upper and lower

extremities

3. Sensory loss of the contralateral face, arm and leg

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4. Ataxia of contralateral extremities
5. Speech impairments/aphasia: Broca's area, Wernicke's or Global aphasia

as a result of a dominant hemisphere lesion (usual y the left brain)

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6. Perceptual deficits: hemispatial neglect, anosognosia, apraxia, and

spatial disorganization as a result of a non-dominant hemisphere lesion

(usual y the right brain)

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7. Visual disorders: d?viation conjugu?e, a gaze preference towards the side

of the lesion; contralateral homonymous hemianopsia

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Note: *faciobrachial deficits greater than that of the lower limb

Posterior cerebral artery
? The posterior cerebral artery

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curls back around the cerebral

peduncle supplying it and the

optic tract, and passes back

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above the tentorium to supply

the inferomedial surface of the

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temporal and occipital lobes

? Its territory meets that of the

anterior cerebral artery at the

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parieto-occipital sulcus.

Its

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branches extend around the

borders of the brain to supply

the inferior temporal gyrus and

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a corresponding strip of cortex

on the lateral surface of the

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occipital lobe. .

Posterior cerebral artery

? The visual area for the

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opposite field of vision lies

whol y within its territory,

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but the middle cerebral

branches can sometimes

extend sufficiently far back

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on the occipital lobe to

supply the macular part of

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the visual area .

? Thus the macular field of

vision may be spared when

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the rest of the visual area is

destroyed by a posterior

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cerebral thrombosis.


Posterior cerebral a. syndrome
1. Visual disorder : Contralateral homonymous hemianopsia & cortical

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blindness with bilateral involvement of the occipital lobe branches

2. visual agnosia
3. dyslexia, Anomic aphasia, color naming and discrimination problems

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4. memory defect
5. involuntary movements: chorea, intention tremor, hemibal ismus
6. contralateral hemiplegia
7. Weber's syndrome: occulomotor nerve palsy
8. B?lint's syndrome: loss of voluntary eye movements optic ataxia,

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asimultagnosia (inability to understand visual objects).

Circle of wil is

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? 1, Internal carotid artery.

? 2, Posterior cerebral

artery.

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8

? 3, Anterior cerebral

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artery.

? 4, Anterior cerebral

artery.

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? 5, Middle cerebral artery.

? 6, Basilar artery.

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? 7, Vertebral artery.
? 8, anterior

communicating artery .

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