1. Anatomy of Cerebrum
- the largestpart of the brain
- dividedinto2parts
diencephalon(central core)
telencephalon(cerebral hemisphere)
DIENCEPHALON
- has 3rd
ventricle &itsboundary
- isa midline structure withsymmetrical rightandleft halves
Grossfeatures
- Inferiorsurface isformedby:
 Hypothalamic
 Optic chiasma
 Optic tract
 Tuber cinerum
 Mammillarybodies
- Superiorsurface concealedbyfornix
- The actual superiorwall of diencephalonisformedbyroof of 3rd
ventricle
- Coveredsuperiorlybyvascularfoldof piamatercalledtelachoroideaof 3rd
ventricle
- Lateral surface of diencephalonisboundedbyinternal capsule of white matter
- Has medial surface
- Medial surface formedbyinitssuperiorpart bymedial surface of thalamusanditsinferior
part by hypothalamus
- The diencephaloncanbe dividedinto4parts:
 Thalamus
 Subthalamus
 Epithalamus
 Hypothalamus
1) Thalamus:
- Large ovoid(egg-shape)massof graymatter
- Form majorpart of diencephalon
- Servesascell stationtoall mainsensorysystem
- Each situatedat side of 3rd
ventricle
- Anteriorendof thalamusisnarrow and rounded
Formsposteriorboundaryof interventricularforamen
- Posteriorendexpandedtoformpulvinarwhichoverhangs:
 Superiorcolliculus
 Superiorbrachium
- Lateral geniculate bodyformssmall elevationonunderaspectof pulvinarlateral portion
- Superiorsurface covered:
 Medially:telachoroidea&fornix
 Laterally:epyndema
- Inferiorsurface iscontinuouswithtegmentumof midbrain

2. - Medial surface of thalamus:
 Form superiorpartof lateral wall of 3rd
ventricle
 Usuallyconnectedtoopposite thalamusbyinterthalamicconnection
- Internal capsule separate thalamuslateral sidefromlentiformnucleus
2)Subthalamus
- inferiortothe thalamus
- betweenthalamus&tegmentumof the midbrain
- collectionof nerve cellsfound atthe cranial endof rod nuclei &substantianigra
- subthalamicnucleushasbiconvex shape
- involve inmuscle activity
3)Epithalamus
- has habenularnucleus&pineal gland
i. habenular nucleus
 small groupof neuronssituatedmedial toposteriorof thalamus
ii. Pineal gland
 Small,conical structure thatattachby pineal stalktodiencephalon
 Projectsbackwardsothat it liesposteriortothe midbrain
 Base of pineal gland:
 Habenularcommisure (at superior)
 Posteriorcommisure (atinferior)
 On microscopicstructure:
 Incomplete dividedintolobulesbyconnectivetissue septa
 2 typesof cell found:
Pinealocytes
Glial cells
 No nerve cell
4)Hypothalamus
- extendsfromregionof opticchiasmatothe caudal borderof mammilarybodies
- liesbelowhypothalamicsulcusonlateral wall of 3rd
ventricle
General appearance of the cerebral hemispheres
- Largestpart of the brain
- Separatedbylongitudinal cerebral fissureatmidline
- Fissure containfalx cerebri =sickled-shapedfoldof duramater
- In the depthof fissure containcorpuscallosumwhichconnectthe hemispheres
- Tentoriumcerebellaseparatedthe cerebral hemispheres
- Folds/ gyri separatedwitheachotherbysulci / fissure
- Each hemisphere dividesto4 lobes:
 Frontal
 Parietal
 Temporal
 Occipital

3. Main Sulci
- Central sulcus: 1)at the anterior= motorcellsthatinitiate opposite site movements
2)At the posterior= general sensorycortex thatreceivefromoppositebody
3)onlysulcusthatindentssuperomedialborder&liesbetween parallel gyri
- Parietal-occipital sulcus:
 beginsonsuperiormedial marginof hemisphere
 passesdownward&anteriorto meetcalcarine sulcus
- Calcarine sulcus:
 foundonmedial surface of hemisphere
Lobes ofcerebral hemisphere
1. Frontal lobe:
- Occupiesareaanteriorto central gyrus
- Occupiesareasuperiortothe lateral sulcus
- Superolateral surface dividedinto3sulci and4 gyri:
- Sulci
I. Precentral sulcus=parallel tocentral sulcus
II. Superiorfrontal sulcus=extendanteriorlyfromprecentral sulcus
III. Inferiorfrontal sulcus=extendanteriorlyfromprecentral sulcus
- Gyri
I. Precentral gyrus= liesbetweenprecentral sulcus
II. Superiorfrontal gyrus= superiortosuperiorfrontal sulcus
III. Middle frontal gyrus=between superiorandinferiorfrontal sulci
IV. Inferiorfrontal gyrus= inferiortoinferiorfrontal sulcus
2. Parietal lobe:
- Occupiesareaposteriortocentral gyrus
- Superiortolateral sulcus
- Lateral surface dividedby2 sulci and3 gyri:
- Sulci
I. Postcentral sulcus=parallel tocentral sulcus
II. Intraparietal sulcus=runningposteriorlyfrommiddle of postcentral sulcus
- Gyri
I. Postcentral gyrus= betweenpostcentral sulcus
II. Superiorparietal lobule (gyrus) =superiortointraparietal sulcus
III. Inferiorparietal lobule (gyrus) =inferiortointraparietalsulcus
3. Temporal lobe :
- Occupiesareainferiortolateral sulcus
- Lateral part dividedto2 sulci & 3 gyri :
- Sulci
I. Superiortemporal sulcus=parallel toposteriorramusof lateral sulcus
II. Middle temporal sulcus=parallel toposteriorramusof lateral sulcus
- Gyri
I. Superiortemporal gyrus
II. Middle temporal gyrus
III. Inferiortemporal gyrus=continuedontoinferiorsurface of hemisphere
4. Occipital lobe:
- Occupiessmall areabehindparieto-occipitalsulcus

4. Medial & inferiorsurfacesof the hemisphere
- Notclearlydefinedonmedial&inferiorsurfaces
- Corpuscallosum= largestcommissure of brain
- Cingulate gyrus:
 beginsbeneaththe anteriorendof corpuscallosum
 continuesabove corpuscallosumuntil itreachesitsposterior end
 separatedfromcorpuscallosumbycallosal sulcus
 separatedfromsuperiorfrontal gyrus bycingulate sulcus
- Paracentral lobule :areaof cerebral cortex surroundsthe indentationproducedbycentral
sulcuson superiorborder
- Precuneus:area of cortex boundedanteriorlybyupturnedposteriorend of cingulated
sulcus& posteriorlybyparieto-occipital sulcus
- Cuneus: triangularareaof cortex boundedabove by parieto-occipital sulcus,inferiorlyby
calcarine sulcus& posteriorlybythe superiormedial margin
- Collateral sulcus:oninferiorsurface of hemisphere
- Lingual gyrusbetweencollateral sulcus&calcarine sulcus
- Parahippocampal gyrusisanteriortolingual gyrus
- Olfactorybulboverliethe olfactorysulcus
- Lateral to olfactorysulcusis orbital gyri.
Internal structure ofthe cerebral hemispheres
- Coveredwithgraymatterlayer= cerebral cortex
- At the inferior:
 Lateral ventricle
 Basal nuclei
 Nerve fibersthat embeddedinneuroglia& part of white matter
1. Lateral Ventricle
- has2 lateral ventricle ineachcerebral hemisphere
- Each has roughlyC-shape cavitylinedwithepyndema&filledwithCSF
- May dividedto:
 Bodywhichoccupiesparietal lobe &fromwhichanterior,posterior&inferiorhorns
extendintofrontal,occipital &temporal lobes respectively.
- Communicateswith3rd
ventricle cavitythrough interventricularforamen
2. Basal Nuclei
- Collectionof massesof graymattersituatedwithineachcerebral hemispheres
 Corpusstriatum:
-Lateral to thalamus
-Dividedintocaudate nucleus& lentiformnucleus
-Caudate nucleus=large C-shapesmassof gray matterthat is closelyrelatedto
lateral ventricle
-Lentiformnucleus=wedge-shapedmassof graymatterwhose broadconvex base is
directedlaterallyanditsblade medially
- Internal capsule separateslentiformnucleusfromcaudate nucleus&thalamus
- External capsule separates lentiformnucleusfromclaustrum
-Function:concerned withmuscularmovement
 AmygdaloidNucleus:
-Inthe temporal lobe close touncus

5. -Partof the limbicsystem
 Claustrum:
-Thinsheetof gray matterthat isseparate fromthe lateral surface of the lentiform
nucleusbyexternal capsule
3. White matter of cerebral hemispheres
- Composedmyelinatednerve fibersof differentdiameterssupportedbyneuroglia
- Classifiedinto3groups:
 Commissural fibers
 Associationfibers
 Projectionfibers
- Commissure fibers
 Connectregionsof 2 hemispheres
 Corpuscallosum= the largestcommisure of brainthat connectcerebral hemisphere
 Corpuscallosumdividedintorostrum,genu,body& splenium
 Rostrum= thinpart of anteriorendof corpuscallosum
 Genu= curvedanteriorendof corpus callosum
 Body= archesposteriorlyandendsasthickenedposteriorportioncalledsplenium
- Association fibers
 Connectvariouscortical regionswithinsame hemisphere
 May dividedtoshort&long groups
 Short associationfiberslie beneaththe cortex &runtransverselytolongaxisof sulci
 Long associationfibers collectedintonamedbundlesthatcanbe dissectedinfor
formalin-hardenedbrain
 Uncinate fasciculusconnectsfirstmotorspeecharea& gyri on inferiorsurface of
frontal lobe withcortex of pole of temporal lobe
 Cingulum=longcurvedfasciculuslyingwithinwhitematterof cingulatedgyrus&it
connectsfrontal & parietal lobeswithparahippocampal&adjacenttemporal cortical
regions
 Superiorlongitudinalfasciculus=largestbundle of nerve fibers thatconnectanterior
part of frontal lobe tooccipital &temporal lobes
 Inferiorlongitudinal fasciculusrunsanteriorlyfromoccipital lobepassing lateral to
the opticradiation
 Frontal-occipitalfasciculusconnectsfrontal lobetooccipital &temporal lobes
- Projectionfibers
 At the upperpart of brainstem = these fibersformcompactbandknownas internal
capsule
 Internal capsule isbentinto anteriorlimb&posteriorlimb
 Theyradiate inall directionstocerebral cortex knownascorona radiata
Cerebral arteries
- The cortical branchesof each cerebral arterysupplysurface &pole of cerebrum
- The cortical branchesof the:
 Anteriorcerebral artery= supplymostof medial &superiorsurfacesof the brain&
frontal lobe
 Middle cerebral artery= supplylateral surface of the brain& temporal lobe

6.  Posteriorcerebral artery=supplythe inferiorsurface of the brain& the occipital
lobe
Cerebral Arterial circle
- Roughlypentagon-shapedcircle of vesselsonventral surface of brain
- Arterial circle isformsequentiallyinananteriortoposteriordirectionbythe:
 Anteriorcommunicating artery
 Anteriorcerebral arteries
 Internal carotid arteries
 Posteriorcommunicating arteries
 Posteriorcerebral arteries