Download MBBS Anatomy PPT 76 Cerebrum Anatomy Notes

Learning Objectives

A Different lobes and surfaces of Cerebral hemisphere

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B. Blood supply of different regions of cerebral hemisphere

C Important sulci and gyri

D Different functional areas located in cerebral hemisphere

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E. Lesions and its effects


2

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Cerebrum

Largest part of the brain

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Heavily convoluted bilobed

structure
4

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Cerebral hemispheres

General Appearance:
Separated by a deep midline sagittal

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fissure ? longitudinal cerebral fissure

In the depth of the fissure, the corpus

cal osum connects the hemispheres

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across the midline

Gyri ? the folds of the surface of

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hemispheres

Sulci ? the fissures separate the gyri

5

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Surfaces of Cerebral Hemisphere

Three surfaces:

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Superolateral surface

Inferior surface

Medial surface

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Borders

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1 Superomedial border

2 Superciliary border and inferolateral border

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(Shows preoccipital notch)

3. Medial orbital border, hippocampal border or

inferomedial border and medial occipital border

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6

Lobes of Cerebral Hemispheres

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Cerebral hemispheres are divided into

lobes by the central, parieto-occipital,

lateral and calcarine sulci

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Lobes are named according to the

cranial bones under which they lie

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Lobes are:
Frontal
Parietal
Temporal
Occipital

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8

Cerebral hemisphere
? the essential features can be

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1

summarized by stating that:-

1. the frontal lobe lies in front of

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the central sulcus (1) and above

2

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the lateral sulcus (2) .

3

2. the parietal lobe is behind the

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central sulcus and above the

lateral sulcus.

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3. the temporal lobe is below the

lateral sulcus

4. the occipital lobe lies below and

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P

behind the parieto-occipital

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F

sulcus (3) .

O

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T
Main sulci

1

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1. Central sulcus

3

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

2

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5. Cingulate sulcus
6. Cal sosal sulcus ( Sulcus

of corpus cal osum )

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7. Orbital sulcus
8. Parahippocampal sulcus
9. Col ateral sulcus

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5

10. Occipiti-temporal sulcus

6

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- First (6) can be seen in

sagittal sections

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- Last 4 seen only in axial

4

sections

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Main sulci

7

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

sulcus

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4. Calcarine sulcus
5. Cingulate sulcus
6. Cal sosal sulcus (

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Sulcus of corpus

10

8

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cal osum )

9

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7. Orbital sulcus
8. Parahippocampal

sulcus

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9. Col ateral sulcus
10. Occipiti-temporal

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

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4. Calcarine sulcus

5. Cingulate sulcus

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

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1

3

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5 6

2

4

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2

2. Parahippocampal sulcus
3. Col ateral sulcus

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4. Occipiti-temporal sulcus

3

4

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Main gyri

1

2

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1. Precentral

3

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2. Postcentral

3

4

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3. Frontal (superior, middle & inferior)

3

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4. Parietal (superior & inferior) 5-

5

5. Temporal (superior, middle &

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inferior)

5

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6. Cal osal

5

7. Medial frontal

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8. Paracentral lobule
9. Precuneus

7

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8

10. Cuneus

6

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11. Lingual gyrus

9

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12. Orbital gyri
13. Gyrus rectus

10

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14. Parahippocampal
15. Occipitotemporal (medial & lateral)

11

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16. Uncus
Main gyri

13

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1. Precentral

2. Postcentral

12

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3. Frontal (superior, middle & inferior)

4. Parietal (superior & inferior) 5-

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5. Temporal (superior, middle &

inferior)

6. Cal osal

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16

7. Medial frontal

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8. Paracentral lobule

15

15

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9. Precuneus

14

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10. Cuneus

11. Lingual gyrus

12. Orbital gyri

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13. Gyrus rectus

14. Parahippocampal

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15. Occipitotemporal (medial & lateral)

16. Uncus
1

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1. Rectus gyrus
2. Uncus ( parahippocampus

gyrus )

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2

3. Hippocampal gyrus

3

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9

Main sulci

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Central sulcus

Indents the superior medial border of the

hemisphere, 1 cm behind the mid-point

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It runs downward, forward and toward the

lateral sulcus across the lateral aspect of the

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hemisphere

The central sulcus is the only sulcus that

indents the superior medial border

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-

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Main sulci (Cont'd)

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Lateral sulcus

Deep cleft on the inferior and lateral

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surfaces of the cerebral hemisphere

It consists of a short stem and three rami

- Anterior horizontal , anterior

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ascending and posterior

11

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Main sulci (Cont'd)

Parieto-occipital sulcus:

Begins on the superior medial border of

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the hemisphere, about 5 cm anterior to

the occipital pole

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It passes downward and anteriorly on the

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

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folded deep within the lateral

sulcus.

? Play a role in consciousness and

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emotions

? The cortical area overlying the

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insula toward the lateral surface of

the brain is the operculum

(meaning lid).

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? The opercula are formed from

parts of the enclosing frontal,

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temporal, and parietal lobes.

? Insulaa is surrounded by circular

sulcus ( arrow !! )

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Superior surface

of temporal

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operculum

presents

anterior and

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posterior

transverse

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temporal gyri
Other Sulci and Gyri

Superolateral su12rface

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Frontal lobe ? anterior to central sulcus

and superior to lateral sulcus

Superolateral surface of frontal lobe is

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divided by three sulci into four gyri

Precentral sulcus and gyrus

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Superior and inferior frontal sulci

Superior, middle and inferior frontal gyri

Anterior and ascending rami of lateral

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sulcus divide inferior frontal gyrus into

PARS ORBITALIS, PARS TRIANGULARIS PARS

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OPERCULARIS
13

15

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Superolateral surface

Parietal lobe ? POST

CENTRAL SULCUS AND

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GYRUS

o INTRAPARIETAL SULCUS

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AND SUPERIOR AND

INFERIOR PARIETAL LOBULE

Lateral

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sulcus
Superolateral surface

o PARIETAL LOBE-Few sulci extend into inferior

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parietal lobule and divided into

o SUPRAMARGINAL GYRUS AROUND LATERAL

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SULCUS

o ANGULAR GYRUS AROUND SUPERIOR

TEMPORAL SULCUS

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o ARCUS TEMPORO-OCCIPITALIS AROUND

INFERIOR TEMPORAL SULCUS

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14

Superolateral surface

Temporal lobe ? inferior to lateral sulcus

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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

gyrus forming primary auditory area, also called

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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

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ORBITAL SULCUS AND ORBITAL GYRI

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

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ANTERIOR END HOOK LIKE LIMITED BY RHINAL SULCUS- UNCUS

MEDIAL AND LATERAL OCCIPITO- TEMPORAL GYRUS

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BLOOD SUPPLY- SUPEROLATERAL

SURFACE

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MIDDLE CEREBRAL ARTERY EXCEPT

STRIP ALONG SUPEROMEDIAL BORDER FROM FRONTAL

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POLE TO PARIETO OCCIPITAL SULCUS BY ACA

OCCIPITAL LOBE AND INFERIOF TEMPORAL GYRUS

EXCLUDING TEMPORAL POLE BY PCA

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BLOOD SUPPLY- INFERIOR

SURFACE

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ACA- MEDIAL PART OF ORBITAL SURFACE

MCA-LATERAL PART OF ORBITAL SURFACE AND

TEMPORAL POLE

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PCA- TENTORIAL SURFACE
BROADMANS AREAS AND

FUNCTIONAL AREAS OF CEREBRAL

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HEMISPHERE

Specific

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Sulci/Fissures:

Central Sulcus

Longitudinal

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Fissure

Sylvian/Latera

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l Fissure

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

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Primary Motor Cortex

/Brodmann,s area 4

Precentral Gyrus ? it cntro

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ls

all voluntary movements of

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the contralateral side of the

body

Site where movements of

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the various parts of the

body are initiated

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Recieves sensory input fro m



cerebellum and thalamus

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The body is represented

upside down along the

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precentral gyrus

Investigation (Phineas Gage)

Primary Motor

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Cortex/ Precentral

Gyrus

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Broca's Area

Orbitofrontal

Cortex

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Olfactory Bulb

Regions

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Modified from:
secondary motor area/6,8,44 and 45
Precentral gyrus,sup,middle,inf frontal gyri
It programs the activity of the PMA
Stronger stimulation is required to produce

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the same degree of movement

Broca's Area ?44,45
Inf.frontal gyrus

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Brings about the formation of words.
Located on Left Frontal Lobe
Broca's Aphasia ? Results in the ability to

comprehend speech, but the decreased

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motor ability (or inability) to speak and

form words
Frontal eye field 8,

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Middle frontal gyrus
Voluntary eye movements towards

opposite side and the

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accomodation pathway

also controls eyelid movements

Prefrontal cortex9,10,11,12

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Concerned with the makeup of the

individual,s personality

Head rotation area

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Parietal Lobe - Cortical Regions

Primary sensorymotor Cortex

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

processing of tactile and proprioceptive

information.

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?Somatosensory Association Cortex -5,7 sup

parietal assists with the integration and

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interpretation of sensations.

?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

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Gyrus

Somatosensory

Association Cortex

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Primary Gustatory

Cortex

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Modified from:

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

Regions

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Occipital Lobe ? Cortical

Regions

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Primary Visual Cortex ? This is the primary area of

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)

Posterior cerebral artery (basilar artery)

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Physiological information about brain

? Left hemisphere is dominant in Which hemisphere

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90% of the right handed and 64%

is dominant ?!

of the left handed

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? Righ hemisphere is dominant in

10% of righ handed and 20% of

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left handed

? In the remaining 16% of left

handed both hemispheres are

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dominant .

? Speech areas in brain usual y in

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the dominant hemisphere !! ( OF

CLINICAL IMPORTANT )
Brodmann areas

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Motor areas of cortex

? 1- primary motor area :-

- MSI area ( precentral gyrus )

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MSI

- MSI area ( Anterior part of

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MSI

paracentral lobule )

? 2- secondary motor area

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? Posterior parts of frontal

gyri extending medial y
Primary motor area

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? Broadmann area 4

? The area Msl is where movements

of the various parts of the body

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are initiated,

MSI

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? Afferent :- receives its main inputs

MSI

from

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the

cerebel um

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and

thalamus.

? Efferent :- the corticonuclear and

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corticospinal (pyramidal) tracts.

? MSI area receives many fibres

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from the basal nuclei and is

concerned

with

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postural

mechanisms, but this area is not

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yet clearly understood.

Motor homunculus

? the body is represented upside

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down along this cortex, although

the face itself is represented the

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right way up.

? The face lies lowest, then the

hand (a very large area), then arm,

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trunk and leg.

? The leg and perineum areas

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overlap the superior border and

extend down on the medial

surface of the hemisphere

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? Blood supply :-

? 1- middle cerebral artery

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? 2- anterior cerebral a. ( leg area )
Primary motor area

? Lesions to this area produce

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contralateral paralysis !!

? Organs that supplied bilateral y

are the less affected ...

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? CNs are supplied bilateral y ?!!

Secondary motor area
? Or supplementary motor area

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? Broadmann are 6
? Location :- Posterior parts of

frontal gyri extending medial y

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? The function of the secondary

motor area:

? 1- To store programs of motor

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activity

resulted

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from

past

experience

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? 2-

Controls

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sequence

of

movements

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? 3- Controls spatial & postural

orientation movements.

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

cerebral arteries
secondary motor area

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? Lesions :-

? Apraxia (inability to execute learned purposeful movements despite

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

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? There is no or little loss of strength

Boca's area

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? The motor (anterior) speech area

(of Broca, areas 44 and 45) is

usual y situated in the inferior

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frontal gyrus on the left side (in

right-handed and in most left-

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handed people), below and in

front of the face area and centred

on the pars triangularis between

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the anterior and ascending rami of

the lateral fissure.

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? Damage to it produces motor

aphasia -- difficulty in finding the

right words, but not paralysis of

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laryngeal musculature.

? Blood supply :-

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? Middle cerebral a.
Wernicke's area

? The posterior speech area (of

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Wernicke) is in the posterior parts of

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 &

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auditory cortex

? Function:

? To understand the written and spoken

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language

? Its integrity is necessary for the

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understanding of speech.

? Lesion ... Receptive dysphasia; the

patient responds by intact, but

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irrelevant speech!

? Blood supply:

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? Middle cerebral artery

Prefrontal cortex
? The prefrontal cortex is an

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extensive area that lies anterior to

the precentral

? The prefrontal area is concerned

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with

1. the makeup of the individual's

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personality.

2. regulator of the person's depth of

feeling.

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3. It also exerts its influence in

determining the initiative and

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judgment of an individual.
Prefrontal cortex

? Lesions :-

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? It is now general y agreed that

destruction of the prefrontal

? region does not produce any

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marked loss of intelligence

? Tumour or traumatic destruction

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of the prefrontal cortex result in

the person's losing initiative and

judgment.

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? Emotional changes that occur

include a tendency to euphoria.

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? The patient no longer conforms to

the accepted mode of social

behavior and becomes careless of

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dress and appearance.

? Bipolar disorders

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? Schizophrenia

Sensory areas

? 1- Primary somatosensory area

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- The postcentral gyrus

1

- Posterior part of l p

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o a

b r

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u alce

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 )

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somatosensory area.

- 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 ...

? Functions to relate the visual

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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

WHY don't we see everything upside-down?

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? -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).

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

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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

medial geniculate body

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? Blood supply:

- Middle cerebral artery

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- Lesions

produce ...

Partial

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deafness in both ears with

inability to locate sound.

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- The greater loss being in the

opposite ear

- (cochlear nuclei send 2nd order to

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the olivary nucleus & nuclei of

trapezoid body bilateral y)

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Auditory pathway

? Explaning why greter loss of

inability to hear on the

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opposite site !!!

? Cochlear n. send fibers more

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to the other side than the

same side ...
Secondary auditory area
? Broadmann area 22

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? Lies posterior to the primary

auditory area

? Function:

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- To interpret sounds and associate

the auditory input with other

sensory information.

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? Blood supply:
? Middle cerebral artery

? Lesions : auditory agnosia !!

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The dominant angular gyrus

? This part is often considered a

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part of the Wernicke area

? Lesion here results in inability to

read (alexia) or write (agraphia).

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Aphasia

Sensory aphasia

Alexia

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Agraphia

Motor aphasia

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A lesion resulting in a nonfluent expressive

aphasia would most likely be found in the

(A) temporal lobe

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(B) parietal lobe

(C) frontal lobe

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(D) occipital lobe
Alexia without agraphia and aphasia would

most likely result from occlusion of the

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(A) left anterior cerebral artery

(B) right anterior cerebral artery

(C) left middle cerebral artery

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(D) left posterior cerebral artery

(E) right posterior cerebral artery

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A patient is asked to bisect a horizontal line

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

and to copy a cross. The patient bisected the

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horizontal line to the left of the midline,

placed all of the numerals of the clock on the

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right side, and did not complete the cross on

the left side. The most likely lesion site for this

deficit is the

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(A) left frontal lobe

(B) right parietal lobe

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(C) left parietal lobe

(D) right temporal lobe

(E) left occipital lobe

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Arterial supply to Brain
? Tissue of the brain ( paranchyme )

al is supplied by two sources ...

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? 1- branches of internal carotid

1

ACA

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MCA

artery

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? 2- branched of basilar artery

2

ECA

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ICA

PCA

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Basialr a.

CCA

Vertebral a.

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Vertebral a.

aorta

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Subcalvain a.

Subcalvain a.

Branches of the vertebral a.

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1. Posterior

inferior

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cerebel ar a.

2. Anterior spinal a.

2

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1
Branches of the basilar a.

1. Anterior inferior cerebel ar a.

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2. Superior cerebel ar a.
3. Posterior cerebral a.

32

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1

Blood supply to Brain
Anterior cerebral artery

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? leaves the internal carotid artery

and passes forwards above the

optic nerve

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? It is connected to its fellow of the

opposite side by the anterior

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communicating artery. It is

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

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cal osum as far back as the parieto-

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.

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

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

curls back around the cerebral

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peduncle supplying it and the

optic tract, and passes back

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above the tentorium to supply

the inferomedial surface of the

temporal and occipital lobes

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? Its territory meets that of the

anterior cerebral artery at the

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parieto-occipital sulcus.

Its

branches extend around the

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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

occipital lobe. .

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Posterior cerebral artery

? The visual area for the

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opposite field of vision lies

whol y within its territory,

but the middle cerebral

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branches can sometimes

extend sufficiently far back

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on the occipital lobe to

supply the macular part of

the visual area .

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? 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

cerebral thrombosis.

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

blindness with bilateral involvement of the occipital lobe branches

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2. visual agnosia
3. dyslexia, Anomic aphasia, color naming and discrimination problems
4. memory defect
5. involuntary movements: chorea, intention tremor, hemibal ismus
6. contralateral hemiplegia

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7. Weber's syndrome: occulomotor nerve palsy
8. B?lint's syndrome: loss of voluntary eye movements optic ataxia,

asimultagnosia (inability to understand visual objects).

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Circle of wil is

? 1, Internal carotid artery.

? 2, Posterior cerebral

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artery.

8

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? 3, Anterior cerebral

artery.

? 4, Anterior cerebral

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artery.

? 5, Middle cerebral artery.

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? 6, Basilar artery.

? 7, Vertebral artery.
? 8, anterior

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communicating artery .

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