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CEREBRUM
MAJ RISHI POKHRELMBBS, MD
NAIHSwww.slideshare.net
CEREBRUM• Cerebral cortex
– Gross anatomy– Sulci and gyri– Functional areas
• White matter• Ventricular system
Borders and surfaces• 4 borders
– Superomedial– Inferolateral with
seprciliary– Medial orbital– Medial occipital
• 3 surfaces– Superolateral– Medial– Inferior
• Orbital• tentorial
7
• 3 Poles
Lobes
Insula
3 surfaces
Sulci and gyri
Functional areas of brain
• Brodmann's area – 47 -52• Based on cytoarchitectonics • Sensory and motor, Primary and association • Multimodal association areas (75%)• Previously denoted by Ms or Sm now by nos
Primary motor areaPrimary sensory areaPremotor area
Frontal eye field
Motor speech (Broca’s) areaLanguage comprehension(Wernicke’s) area
Primary visual area
Leg Leg
Arm Arm
FaceFace
Pharynx
Larynx
Important Areas
Auditory area
Frontal Lobe
Frontal Lobe
Parietal Lobe
Parietal Lobe
Parietal Lobe
43
Temporal Lobe
Occipital Lobe
Medial Surface
Homunculus
Important Areas
Important Areas
Applied anatomy
• Collection of nerve fibres: Tracts, Fasciculi,
Lemnisci, Peduncles, Commissure etc.
• Myelination: Oligodendrocytes in CNS &
Schwann cells in PNS
• Collection of nerve cell bodies within white
matter of CNS: nuclei
WHITE MATTER OF CEREBRUM
CLASSIFICATION OF NERVE FIBERS
• Association Fibres: Connect
different cortical areas of the
same hemisphere
• Commissural Fibres: Connect
wide areas of Cx of both
hemispheres across midline
• Projection Fibres: Connect
cerebral cx with subcortical
grey matter of BG, Thalamus,
Brain stem & Spinal cord
ASSOCIATION FIBRES
Short and Long
LONG ASSOCIATION FIBRES
• Uncinate Fasciculus : – Connects Broca’s area
with Temp pole & Superior Temp Gyrus
– Expression of speech• Cingulam :
– Connects various parts of Limbic lobe (Cingulate & Parahippocampal gyri)
• Sup Longitudinal Fasciculus : Lateral to Corona radiata– Frontal lobe with visual
asso areas & Temporal lobe
• Fronto-occipital fasciculus : Medial to C Radiata– Frontal lobe with
Occipital & Temp lobes• Inferior Longitudinal
Fasciculus : Temp lobe with Areas 18 & 19 of occipital lobe
COMMISSURAL FIBRES
Types:• Homotopical : Connect
identical areas• Heterotopical : Connect
non-identical areas
Examples :• Corpus callosum • Ant commissure, Post
commissure • Hippocampal &
Habenular commissures
AP
CORPUS CALLOSUM
• Largest band of commissural fibres which connects wide areas of Neocortex except lower and ant parts
of temporal lobe
• Well developed in man
• 300 million finely myelinated fibres
• 10 cms long
Location :
• Ant end : 4cm behind frontal pole • Post end : 6cm in front of Occipital pole
AP
CORPUS CALLOSUM
PARTS : Splenium, Trunk, Genu, Rostrum
• Rostrum - continuous below with Lamina terminalis
A P
Forceps Major
Forceps Minor
CORPUS CALLOSUM
• Rostrum: orbital surfaces of 2 frontal lobes• Forceps minor: fibers of genu – 2 frontal lobes• Tapetum: fibers of trunk and splenium – do
not intersect with corona radiata, forms roof and lateral wall of post horn and lateral wall of inferior horn of lateral ventricles.
• Forceps major: fibers of splenium – 2 occipital lobes.
CORPUS CALLOSUM : TAPETUM
TAPETUMForceps major
LAT VENTRICLE : POSTERIOR HORN
LAT VENTRICLE : INFERIOR HORN
TAPETUM OF CC
Stria terminalis (Med)
Tail of Caudate Nu
INF HORN
Collateral eminence
CORPUS CALLOSUM
Function : • Interhemispheric transfer of information essential for
bilateral response & learning process
Applied : • congenital absence / surgical divn does not produce
any serious neurological deficit
Split brain syndrome :
COMMISSURAL FIBRES – Cont’d
• Ant commissure : – Ant part : Allocortex– Post part : Neocortex
• Post commissure : – Connect Sup colliculi, Pretectal nuclei, Nu of post
commissure, Interstitial nu etc.– Role in consensual pupillary light reflex
• Hippocampal commissure : Connects crura of Fornix• Habenular commissure : Connect habenular Nu (Limbic
system)
WHITE MATTER : CEREBRUM
PROJECTION FIBRES
• Connect cerebral cx with
subcortical grey matter like BG,
Thalamus, Brain stem & Spinal
cord.
• Cortico-fugal & cortico-petal
fibres
• E.g. Corona radiata & Int
capsule of Neo cortex
Fimbriae & Fornix of Allocortex
CORONA RADIATA
• Fan shaped arrangement of projection fibers from neo-cortex converging to the periphery of Corpus striatum
• Continues below as Internal capsule
CORONA RADIATA
INTERNAL CAPSULE• A compact band of
neocortical projection fibres
• Main highway for input &
output fibres of cerebral cx
• Continues above as corona
radiata & below as crus
cerebri of midbrain
• V- shaped in horizontal
section with concavity
laterally
RELATIONS : • Medial : Head of Caudate Nu & Thalamus• Lateral : Lentiform Nucleus
MedialExtreme capsule
Lateral
INTERNAL CAPSULE HORIZANTAL SECTION
• Ant Limb
• Genu
• Post limb
• Retrolentiform part
• Sublentiform part
ARRANGEMENT OF FIBRES :
:
Cortico-reticular
Ant Thalamic radiationAnt Thal Nu –Cingulate Gyrus (Papez
Circuit)Fibres of MF Bundle
ARRANGEMENT OF FIBRES : GENU
• Cortico- nuclear fibres : from areas 4, 6 & 8 to
motor nuclei of cranial nerves (contralateral)
• Superior Thalamic radiation : Thalamus to pre &
post central gyri of cerebral cortex
• Corticoreticular
ARRANGEMENT OF FIBRES: POSTERIOR LIMB – From Globus pallidus
• To Subthalamic nucleus (Fasciculus subthalamicus)
• To Thalamus (Fasciculus Lenticularis)– Nigro - striate (Comb bundle)
• From Substantia Nigra to Caudate Nu & Putamen
– Thalamo-striate : From intralaminar & centromedian Nu to Caudate Nu & Putamen
ARRANGEMENT OF FIBRES: SUBLENTIFORM PART• Auditory Radiation
– MGB to Anterior Transverse Temp gyrus & Sup temporal gyrus– Perception of hearing
• Meyer’s loop of optic radiation– from lower part of peripheral retina to visual Cortex
• Temporo - pontine & Parieto – pontine fibres
ARRANGEMENT OF FIBRES: RETROLENTIFORM PART
- Optic Radiation : LGB to Area 17
- Area 18,19 to Sup Colliculus & Motor Nu of EO Muscles for conjugated movements of eye
balls
- Parieto & Occipeto - pontine fibres
- Post Thalamic Radiation : Pulvinar (thalamus) to Areas 18,19, 39, 40)
ARTERIAL SUPPLY OF I C
Striate br of MCA
Recurrent branch of ACA
Striate br of AC A
Ant Limb
Genu
Sublentiform part
Post Limb
Retrolentiform part
Ant cerebral Artery
Int Carotid ArteryMiddle cerbral A
Post Cerebral Atery
Ant choroidal A
By central branches of cerebral arteries - End arteries
70
INT CAPSULE : BLOOD SUPPLY
ARTERY
PART OF IC
Striate Br of ACA
Rec Br of ACA
Striate Br of MCA(Charcot’s artery)
Direct Br from ICA
Ant Choroidal A
P CA
Ant Limb Genu
Post LimbS L Part
RL Part
By central branches of cerebral arteries - End arteries
APPLIED ANATOMY
• Cerebrovascular accident (CVA) affecting int capsule cause extensive clinical effects – Blood supply by end arteries– Dense collection of fibres in IC– Caused commonly by hemorrhage from Charcot’s
artery• Hemiplegia :
– UMN type paralysis of one half of the body – Commonly caused by CVAs affecting IC
Ventricular system
• Communicate with each other & with SA Space (thru roof of 4th Ventricle)
• Allow free flow of CSF produced by Choroid plexus
PART SUB DIVN CAVITY
FORE BRAINTelencephalon Lateral ventricle(s)
Diencephalon 3rd Ventricle
MID BRAIN Cerebral Aqueduct
HIND BRAIN 4th Ventricle
SP CORD Central canal
LATERAL VENTRICLE
• Cavity of Telencephalon
• One in each cerebral hemisphere
• Roughly ‘C’- shaped
• Capacity : 7-10ml
PARTS :
• Body (Central part)
• Anterior (Frontal lobe)
• Posterior (Occipital lobe)
• Inferior (Temporal lobe)
Task
• Draw a labeled diagram of
– Coronal section through
• Ant horn of lat ventricle
• Body of lat ventricle
• Inf horn of lateral ventricle
• Post horn of lat ventricle
– Floor of 4th ventricle
?