anatomy of cerebrum

1. CEREBRUM
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3. What's wrong with this picture?

4. CEREBRUM
• Cerebral cortex
–Gross anatomy
–Sulci and gyri
–Functional areas
• White matter
• Ventricular system

5. Borders and surfaces
• 3 borders
– Superomedial
– Inferolateral with
seprciliary
– Medial
• Medial orbital
• Medial occipital
• 3 surfaces
– Superolateral
– Medial
– Inferior
• Orbital
• tentorial

7. 7
• 3 Poles

8. superolateral surface

9. medial surface

10. inferior surface

11. Lobes

12. Insula

13. Sulci and gyri

14. a: pars orbitalis
b: pars triangularis
C: pars opercularis

17. 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

20. Primary motor area
Primary sensory areaPremotor area
Frontal eye field
Motor speech (Broca’s) area
Language comprehension
(Wernicke’s) area
Primary visual area
Leg
Leg
Arm
Arm
Face
Face
Pharynx
Larynx
Important Areas
Auditory area

21. Frontal Lobe

22. Frontal Lobe

23. Parietal Lobe

24. Parietal Lobe

25. Parietal Lobe
43

26. Temporal Lobe

27. Occipital Lobe

28. Medial Surface

29. Homunculus

30. Important Areas

31. Important Areas

32. Applied anatomy

38. • 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

39. 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

40. ASSOCIATION FIBRES
Short and Long

41. 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)

42. • 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

43. COMMISSURAL FIBRES
Types:
• Homotopical : Connect
identical areas
• Heterotopical : Connect
non-identical areas
Examples :
• Corpus callosum
• Ant commissure, Post
commissure
• Hippocampal &
Habenular commissures
AP

44. 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

45. CORPUS CALLOSUM
PARTS : Splenium, Trunk, Genu, Rostrum
• Rostrum - continuous below with Lamina terminalis
A P

46. Forceps Major
Forceps Minor
CORPUS CALLOSUM

48. • 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.

49. CORPUS CALLOSUM : TAPETUM
TAPETUM
Forceps major
LAT VENTRICLE : POSTERIOR HORN

50. LAT VENTRICLE : INFERIOR HORN
TAPETUM OF CC
Stria terminalis (Med)
Tail of Caudate Nu
INF HORN
Collateral
eminence

51. 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 :

52. 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)

53. 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

54. 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

55. 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

56. RELATIONS :
• Medial : Head of Caudate Nu & Thalamus
• Lateral : Lentiform Nucleus
Medial
Extreme capsule
Lateral

57. INTERNAL CAPSULE HORIZANTAL SECTION
• Ant Limb
• Genu
• Post limb
• Retrolentiform part
• Sublentiform part

58. ARRANGEMENT OF FIBRES :
:
Cortico-reticular
Ant Thalamic radiation
Ant Thal Nu –Cingulate Gyrus (Papez
Circuit)
Fibres of MF Bundle

59. 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

60. 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

61. 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

62. 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)

63. 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 Artery
Middle cerbral A
Post Cerebral Atery
Ant choroidal A
By central branches of cerebral arteries - End arteries

64. 70

65. 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
Limb
S L Part
RL Part
By central branches of cerebral arteries - End arteries

66. 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

67. Ventricular system
• Communicate with each other & with SA Space (thru roof of
4th Ventricle)
• Allow free flow of CSF produced by Choroid plexus

68. PART SUB DIVN CAVITY
FORE BRAIN
Telencephalon Lateral ventricle(s)
Diencephalon 3rd Ventricle
MID BRAIN Cerebral Aqueduct
HIND BRAIN 4th Ventricle
SP CORD Central canal

69. 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)

70. 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