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Cerebrum

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anatomy of cerebrum

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Cerebrum

  1. 1. CEREBRUM www.slideshare.net
  2. 2. What's wrong with this picture?
  3. 3. CEREBRUM • Cerebral cortex –Gross anatomy –Sulci and gyri –Functional areas • White matter • Ventricular system
  4. 4. Borders and surfaces • 3 borders – Superomedial – Inferolateral with seprciliary – Medial • Medial orbital • Medial occipital • 3 surfaces – Superolateral – Medial – Inferior • Orbital • tentorial
  5. 5. 7 • 3 Poles
  6. 6. superolateral surface
  7. 7. medial surface
  8. 8. inferior surface
  9. 9. Lobes
  10. 10. Insula
  11. 11. Sulci and gyri
  12. 12. a: pars orbitalis b: pars triangularis C: pars opercularis
  13. 13. 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
  14. 14. 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
  15. 15. Frontal Lobe
  16. 16. Frontal Lobe
  17. 17. Parietal Lobe
  18. 18. Parietal Lobe
  19. 19. Parietal Lobe 43
  20. 20. Temporal Lobe
  21. 21. Occipital Lobe
  22. 22. Medial Surface
  23. 23. Homunculus
  24. 24. Important Areas
  25. 25. Important Areas
  26. 26. Applied anatomy
  27. 27. • 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
  28. 28. 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
  29. 29. ASSOCIATION FIBRES Short and Long
  30. 30. 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)
  31. 31. • 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
  32. 32. COMMISSURAL FIBRES Types: • Homotopical : Connect identical areas • Heterotopical : Connect non-identical areas Examples : • Corpus callosum • Ant commissure, Post commissure • Hippocampal & Habenular commissures AP
  33. 33. 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
  34. 34. CORPUS CALLOSUM PARTS : Splenium, Trunk, Genu, Rostrum • Rostrum - continuous below with Lamina terminalis A P
  35. 35. Forceps Major Forceps Minor CORPUS CALLOSUM
  36. 36. • 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.
  37. 37. CORPUS CALLOSUM : TAPETUM TAPETUM Forceps major LAT VENTRICLE : POSTERIOR HORN
  38. 38. LAT VENTRICLE : INFERIOR HORN TAPETUM OF CC Stria terminalis (Med) Tail of Caudate Nu INF HORN Collateral eminence
  39. 39. 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 :
  40. 40. 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)
  41. 41. 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
  42. 42. 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
  43. 43. 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
  44. 44. RELATIONS : • Medial : Head of Caudate Nu & Thalamus • Lateral : Lentiform Nucleus Medial Extreme capsule Lateral
  45. 45. INTERNAL CAPSULE HORIZANTAL SECTION • Ant Limb • Genu • Post limb • Retrolentiform part • Sublentiform part
  46. 46. ARRANGEMENT OF FIBRES : : Cortico-reticular Ant Thalamic radiation Ant Thal Nu –Cingulate Gyrus (Papez Circuit) Fibres of MF Bundle
  47. 47. 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
  48. 48. 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
  49. 49. 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
  50. 50. 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)
  51. 51. 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
  52. 52. 70
  53. 53. 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
  54. 54. 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
  55. 55. Ventricular system • Communicate with each other & with SA Space (thru roof of 4th Ventricle) • Allow free flow of CSF produced by Choroid plexus
  56. 56. 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
  57. 57. 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)
  58. 58. 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

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