2. INTRODUCTION
The cerebrum is the largest part of the brain with two
hemisphere.The two cerebral hemisphere are linked by
commisural fibres of corpus callosum.
Each cerebral hemisphere contains externally highly
convulated cortex of grey matter and internal mass of white
matter or medulla.
Each cerebral hemisphere contains lateral venticle continous
with the third ventricle through interventricular foramen.
The cerebral hemispheres contains motor and sensory areas
and the limbic system.
Each cerebral cortex is often divided phylogenetically into old
allocortex,consisting of archicortex and paleocortex and a
newer neocortex.
5. Surfaces of cerebral hemisphere
Each cerebral hemisphere
has three surfaces
• Superolateral surface
• Medial surface
• Inferior surface.
Inferior surface further
divided into two
vi. Orbital surface
vii.Tentorial surface
6. Surfaces of cerebral hemisphere………contd.
Superolateral surface
It follows the concavity of the cranial vault
Medial surface
It is flat and vertical and seperated from its fellow by the great
longitudinal fissure and falx cerebri.
Inferior surface
Inferior surface or the basal surface is irregular and divided
into orbital and tentorial surface.
11. Lobes of the brain
Four lobes are
present
• Frontal
• Parietal
• Occipital
• Temporal
Occasionally
insula is
considered as
the fifth lobe
12. Gyrus and sulcuses
Each cerebral hemisphere
convulation called Gyrus
The gyruses are separated
by furrows of varying length
called Sulci.
The convulated structure
increases the cortical
volume to three times what
it would be if the surface is
smooth.
The area of the cerebral
cortex is 2200cm²
Sulci
(Groove)
Fissure
(Deep groove)
Gyri
shows a complex pattern of (Elevation)
13. Important sulci and gyri
In the suprolateral surface:
ii. Lateral sulcus
o Deep cleft on the lateral
and inferior surface
o It has a stem which divides
into three
rami:anterior,ascending,p-
osterior.
o The floor of the posterior
ramus is the insula which is
hidden cortex.
Lateral sulcus
Central sulcus
14. Important sulcus and gyrus…….contd.
ii. The central sulcus
o It is the boundary between frontal and parietal lobes
o It starts at the superomedial border, a little behind the
midpoint between frontal and occipital poles.It runs
downards and forwards for about 8-10cm to end little above
the posterior ramus of lateral sulcus.
o It demarcates the motor and sensory area of the cerebral
cortex.
iii. The other known sulcuses are
superior frontal sulcus
Inferior frontal sulcus
Precentral sulcus
Postcentral sulcus
15. Medial surface
In the medial surface
The commisural fibres of
the corpus callosum lies in
the depth of longitudinal
fissure
Parts of corpus callosum
d. Rostrum
e. Genu
f. Trunk or body
g. Splenium
The anterior part divided
into outer and inner zone
by cingulate sulcus
18. Sulcus and gyrus………contd.
The posterior region of the medial surface is traversed by
parieto-occipital and calcarine sulcus.The parieto-
occipital sulcus marks the boundary between parietal
and occipital lobes.
The visual cortex lies above and below the calcarine
sulcus.
In the inferior cerebral surface
Olfactory sulcus
Rhinal sulcus
Occipitotemporal sulcus
Collateral sulcus
20. Insula
-Present within the lateral sulcus
Between temporal and frontal
Lobe.
-The overlying cortical areas are
called opercula formed from the
parts of frontal,temporal and
parietal lobe
-Functions linked to emotion and
body’s homeostasis
-i.e perception,motor control,self
awarness,congnitive functioning
interpersonal experience
Insula
21. Cerebral cortex
Cerebral cortex is an intricate blend of nerve cells and
fibres,neuroglia and blood vessels.
Microscopically the cortex consists of six layers or laminae
lying parallel to the surface.
From outside to inside
IV.Molecular or plexiform layer
V. The external granular layer
VI.External pyramidal lamina
VII.Internal granular layer
VIII.Internal pyramidal cell layer
IX.Multiform or pleiomorphic layer
23. Neocortex has 6 layers
designated I, II, III, IV, V, VI
Pyramidal cells
predominate in layers III
and V
Granule cells in layers II and
IV
Pyramidal cells
Granule cells
Cerebral
cortex
24. Pyramidal cells have large apical
dendrite and basal dendrites
Axon projects downward into
subcortical white matter; may have
collaterals
Pyramidal cell is the primary output
neuron
PY R A MIDA L
C E L L
26. Broadmann’s areas
These areas were defined and
numbered by korbinian
broadmann
The areas are based on the
cortical cytoarchitectonic
organisation of neurons
Many of the broadmann’s areas
are defined on neurological
function coorelated closely to
diverse cortical functions.
For example
Area 1,2,3 – primary
somatosensory area
Area 4 – Motor area
Area 41,42 – Auditory area
Area 44,45 – Broca’s area,etc
28. •Primary Motor Cortex (Precentral Gyrus) – Cortical site
involved with controlling movements of the body.
•Broca’s Area – Controls facial neurons, speech, and language
comprehension. Located on Left FrontalLobe.
Broca’s Aphasia – Results in the ability to comprehend speech, but
the decreased motor ability (or inability) to speak and form words.
Orbitofrontal Cortex – Site of Frontal Lobotomies
* Desired Effects:
- Diminished Rage
- Decreased Aggression
- Poor Emotional Responses
* Possible Side Effects:
- Epilepsy
- Poor Emotional Responses
-Perseveration
(Uncontrolled, repetitive
actions, gestures, or words)
Frontal lobes cortical regions
Primary motor cortex
Broca’s area
Orbitofrontal cortex
29. Parietal lobe cortical
areas
Primary Somatosensory Cortex
(Postcentral Gyrus) – Site involved with
processing of tactile and proprioceptive
information.
Associated s o ma to s ens o ry
area(7)
Somatosensory Association Cortex -
Assists with the integration and interpretation of
sensations relative to body position and
orientation in space. May assist with visuo-
motor coordination
Primary Gustatory Cortex – Primary site
involved with the interpretation of the
sensation of Taste.
Primary gustatory
area (40)
Primary somatosensory area
(3, 1, 2)
30. Primary Visual Cortex – This is the
primary area of the brain
responsible for sight -recognition
of size, color, light, motion,
dimensions, etc.
Visual Association Area –
Interprets information acquired
through the primary visual cortex.
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31. White matter of cerebrum
Consists of myelinated nerve
fibres which are categorized
on the basis of their course
and connections
B. Association fibres
• It links different cortical areas
of the same hemisphere
• Two types
v. Short association fibres
They are entirely intracotical
Some merely pass from one
wall of the sulcus to other.
viii.Long association fibres
They are present in bundles
Example: uncinate
fasciculus,cingulum,superior
longitudinal fasciculus,etc
32. White matter of cerebrum………contd.
A. Commissural(transverse)
fibres
• Commisural fibres cross the
midline,linking
corresponding areas in the
two cerebral hemisphere.
• The largest commissure is
the corpus callosum.Other
commisures are
• Anterior
• Posterior
• Habenular
• Commissure of the fornix.
33. White matter of cerebrum……..contd.
•
A. Projection fibres
Projection fibres connect
cerebral cortex with lower
levels in the brain and
spinal cord.
• Consists of both
coticofugal and
corticopetal fibres
• Corticofugal fibres
converge from all
directions to form corona
radiata.Corona radiata
continous with the
internal capsule.
38. .A non-progressive
disorder
•Caused by brain injury
pre (70-80%), peri, or
post natally
•Injure occurs before
CNS reaches maturity
•Patients often have great
potential masked by their
connections
CE RE B RA L PA L S Y
Manifestation
• Malfunction of motor centers
•Postural and balance
difficulties
•Normal life expectancy
possible
• Early death respiratory
39. Spastic
• 52-70% of all CPs
• Hyperirritability of muscles
• Arms flexed, legs internally rotated
• Difficulty bending into a sitting position
• Difficulty with head control
• Postural difficulty
• May not have protective extension
Athetoid or Dyskinetic Type
• 25- 30% of CPs
•Uncontrollable writhing movements of
opposing muscle groups
• All four extremities involved
• Neck and face involved
• Voluntary movements are flailing
• Difficulty uprighting and balancing
•Grimacing
40. Other types
• Tremors (rare form) of CP
• Rigid 5 -10% of CPs
• Flaccid (Hypotonicity)
• Mixed 15 - 40% of CPs
• 5 to 10 %
• Affects balance and coordination.
•They may walk with an unsteady gait with feet
far apart, and they have difficulty with
motions that require precise coordination,
such as writing.
Ataxic cerebral palsy
42. SKULL BASE
Skull base boundaries: Upper surface of the ethmoid
bone,orbital plate of the frontal
bone upto the ethmoid bone
Key bones:
Orbital Plate of frontal bone
Ethmoid bone
Sphenoid bone
Occipital bone
43. Skull base……contd.
Divided into three cranial fossa:
a. Anterior cranial fossa
b. Middle cranial fossa
c. Posterior cranial fossa
44. Key openings in base of the skull
Foramenspinosum
Foramen ovale
Foramen lacerum
Foramen rotundum
Foramenmagnum
Jugular foramen
Superior orbital fissure
Inferior orbital fissure
Optic canal
Hypoglossal canal
Pterygopalatine fossa
Skull base……contd.
45. Foramen rotundum
Present at the anterior
and medial part of
sphenoid bone.
Structures passing
d.Maxillary nerve
e.Emissary veins
46. Foramen ovale
Located in the anterior
part of sphenoid
bone,posterolateral to
foramen rotundum
Structures passing
• Mandibular nerve
•Accessory meningeal
artey
• Lesser petrosal nerve
• Emissary veins
47. Foramen spinosum
Foramen spinosum
may be absent in 2% of
the cases.
Situated
posterolateral to
foramen ovale
Transmits following
structures
•Middle meningeal
artery
•Nervous spinosus from
mandibular nerve
• Middle meninigeal vein
48. Foramen magnum
Latin”great hole” is
present in the occipital
bone
It transmits
•Medulla
oblongata,vertebral
arteries
•Anterior and Posterior
spinal arteries
• Spinal accessory nerve
•Membrana tectoria,Alar
ligaments.
49. Superior Orbital Fissure
•CN III, IV, V1, VI
•Middle meningeal artery-
orbital branch
• Recurrent meningeal artery
• Superior opthalmic vein
Jugular foramen
Anterior compartment
• Inferior petrosal sinus
•
•
•
intermediate compartment
Cranial nerve IX,X,XI
Posterior compartment
Internal jogular vein
Meningeal branches of
occipital and ascending
pharyngeal artery
