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Meninges of brain & Grey matter of Spinal cord

Detailed description of internal structure of spinal cord.

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Meninges of brain & Grey matter of Spinal cord

  1. 1. DR. MEHUL TANDEL
  2. 2. The Meninges
  3. 3. OBJECTIVES • Three layers • Subarachnoid space • Cisternae • Applied anatomy
  4. 4. The Meninges
  5. 5. The Meninges 1. Dura mater - strong, "Tough mother" • 2.2. ArachnoidArachnoid -- spidery, holds bloodspidery, holds blood vesselsvessels • 3.3. Pia materPia mater -- "delicate mother""delicate mother" Pachymeninx Thick Leptomeninx Thin
  6. 6. The Meninges
  7. 7. DURA MATER • Thick dense inelastic membrane form outermost covering of brain & spinal cord • Bilaminar: • Endosteal layer (outer) • Meningeal layer (inner)
  8. 8. DURA MATER • Endosteal layer ; – Inner Periosteum – Not continuous with dura mater of spinal cord • Meningeal layer ; – Covering the brain – Continuous with dura mater of spinal cord – Folded inwards as 4 septa between part of the brain – Function of septa?
  9. 9. duramater
  10. 10. Coronal section of the upper part of the head Endosteal layer Meningeal layer They are closely united except along certain lines; they are separated to form venous sinuses Superior sagittal sinus (Dural venous sinus) Dura mater
  11. 11. Extradural Haematoma
  12. 12. Arachnoid Mater  Thin, impermeable & avascular membrane covering the brain  Subdural spaceSubdural space (filled by a film of fluid)  Subarachnoid spaceSubarachnoid space (filled with CSF)  Covered by mesothelial cells
  13. 13. Arachnoid mater
  14. 14. Arachnoid Villi & Granulation Arachnoid villi Arachnoid mater Subarachnoid space Arachnoid granulations Subdural space Sites for CSF absorption
  15. 15. Subdural Space : Superior cerebral veins beneath arachnoid
  16. 16. Subdural Haematoma * Dura Arachnoid
  17. 17. Pia Mater • Thin delicate vascular membrane closely invests the surface of the brain and spinal cord • Covering the gyri, descending into the deepest sulci
  18. 18. Pia mater Pia mater
  19. 19. Pia Mater  Perivascular sheath: Virchow – Robin’s Space  Over the cranial nerves & fuses with their epineurium  TELA CHOROIDAE:  Choroid plexus:  Forms CSF
  20. 20. Tela Choroidae & Choroid Plexus Site of Formation of CSF
  21. 21. Subarachnoid Space
  22. 22. Subarachnoid Cisternae  Arachnoid and pia are widely separated contain pool of CSF  Cisterna cerebellomedularis  Cisterna Magna  Cisterna Pontis  Cisterna interpeduncularis  Cisterna of Lateral Sulcus  Cisterna Ambiens  Lumbar Cisternae
  23. 23. Median sagittal section to show the subarachnoid cisterns & circulation of CSF Superior cistern(ambiens) Interpeduncular cistern Cerebellomedullary cistern Chiasmatic cistern Pontine cistern
  24. 24. Cisterna Interpeduncularis Lumbar Cisternae
  25. 25. * Subarachnoid haemorrage Dura Arachnoid Pia mater
  26. 26. SPINAL CORD
  27. 27. OBJECTIVES • External structure of the spinal cord • Internal structure of the spinal cord – Grey Matter • Anterior grey column – Neurons – Columnar Arrangement • Posterior grey column – Neurons – Columnar Arrangement – Laminar concept of grey matter
  28. 28. EXTERNAL FETURES • Cylindrical in shape • Foramen magnum  L1/L2 (adult) L3 (newborn) • Occupies upper ⅔ of vertebral canal
  29. 29. Structure Of The Spinal Cord
  30. 30. External Features Anterior median Fissure Antero-lateral sulcus Antero-lateral sulcus Posterior median Sulcus Postero-lateral sulcus Postero- intermediate sulcus
  31. 31. Ventral Grey Horn Lateral Horn Dorsal Grey Horn Motor Sensory Autonomic Grey Matter Neurons, Neuroglia BV
  32. 32. Ventral Grey Column Intermediate grey column Dorsal Grey Column
  33. 33. Head Short & Broad Ventral Grey Horn Base
  34. 34. Dorsolateral tract Long & Narrow Dorsal Grey Horn Apex Head Neck Base
  35. 35. Preganglionic- Autonomic Intermediate / Lateral Grey Horn T1 – L2 (Sympathetic) S2 – S4 (Para-sympathetic)
  36. 36. Grey Commissure Central part Central Canal Ventral Grey Commissure Dorsal Grey Commissure Crossing fibers
  37. 37. Anterior White Funiculus Lateral White Funiculus Posterior White Funiculus White Matter Nerve fibers, Neuroglia, BV Fasciculus Gracilis Fasciculus Cuneatus
  38. 38. • Neurons: – Motor - α, β, γ – Interneuron • Axons pass through anterior nerve roots as Final common pathway Anterior grey columns
  39. 39. • Alpha(α): – Multipolar – Golgi type 1 – Thickly myelinated – Efferent – supply extrafusal muscle fibres – Motor Unit: • Large – 100 – 200 , Gross Movements • Small - 5 – 10, fine movements
  40. 40. • Gamma(γ): – Multipolar – Golgi type 1 – Thinly myelinated – Efferent – Intrafusal muscle fibres = Muscle Spindle – Reflex control of muscle tone
  41. 41. • Beta(β): – Multipolar – Intermediate size – Efferent – supply extrafusal & intrafusal fibres • Interneuron: – Multipolar – Golgi Type II – Confined within grey matter – Reflex activites • Monosynaptic • Polysynaptic
  42. 42. Nerve cells group in the Anterior gray Columns • 3 nerve cell groups –Medial –Lateral –Central
  43. 43. • Medial: –Entire spinal cord –Subdivide: Ventero-medial Dorso-medial Trunk
  44. 44. • Lateral: – Cervical (C4 – T2) & Lumbosacral enlargements (L2 – S3) – Subdivide in to: Arm & Thigh Forearm & Leg Hand & Foot Ventero-lateral Dorso-lateral Retro-dorso-lateral
  45. 45. • Central –Present in different regions C3 – C5 Phrenic C1 – C5 Spinal Accessory Lumbosacral L2 – S3
  46. 46. • Neurons: – Interneuron – Tract Cells Posterior grey columns • Interneuron: – Reflex – Receive terminals of descending pathway – Project to α, & γ neuron
  47. 47. • Tract Cells: – Multipolar – Golgi type 1 – Thickly myelinated – Axons pass ipsilaterally, contralaterally or bilaterally and Form Ascending Tracts : Spino-thalamic Spino-tectal Spino-reticular Spino-cerebellar Cell bodies of Ascending Tracts of Posterior white funiculi (FG & FC) located in DRG
  48. 48. Nerve cells group in the Posterior gray Columns • 5 nerve cell groups – Postero-marginal nucleus – Substantia gelatinosa of Rolando – Nucleus proprius – Nucleus dorsalis (Clarke’s column) – Visceral afferent nucleus
  49. 49. Postero-marginal nucleus Substantia gelatinosa Nucleus proprius Visceral afferent nucleus Nucleus dorsalis (Clarke’s column)
  50. 50. • Postero-Marginal Nucleus / Marginal Nucleus – Over the apex – Throughout the entire length of spinal cord – Afferent from dorsal nerve roots: Pain & Temperature – Origin to spino-thalamic tracts
  51. 51. • Substantia gelatinosa – At the apex – Throughout the entire length of spinal cord – Mainly consist of – Interneurons(Golgi Type II neurons) – Afferent from Lateral division of dorsal nerve roots- Pain & Temperature
  52. 52. • Nucleus proprius – Head & Neck of posterior grey column – Whole length of spinal cord – Main bulk of cells in posterior gray column – Afferent from both Lateral & Medial division of dorsal nerve roots with proprioception, 2-point discrimination & vibration Spino-thalamic tract
  53. 53. • Nucleus dorsalis (Clarke’s column) – Medial part of base – C8 – L2 / L3 – Proprioceptive & exteroceptive from Lower limb & trunk through collateral branches of post tracts – Axon – form post spino-cereballar tract
  54. 54. • Visceral afferent nucleus – Base - lateral to nucleus dorsalis – T1 – L2/3, S2 – S4 – receives sensations from viscera
  55. 55. – Lateral Horn – T1 – L2/3, S2 – S4 – Intermedio-lateral & Intermedio-medial – Preganglionic neuron of ANS • T1 – L2/3 : Thoraco-lumbar, Sympathetic • S2 – S4 : Parasympathetic – Pelvic Splanchnic nerve Intermediate Grey Columns
  56. 56. • Based on Connections, Cyto-architecture & Packing density • Total 10 Laminae Laminar Concept – Rexed Laminae X IX X - Substantia Gelatinosa centralis
  57. 57. Rexed Laminae • Lamina I – Marginal nucleus • Lamina II – Substantia Gelatinosa • Lamina III & IV – Nucleus Proprius – Afferents from Skin: Laminae I – IV • Lamina V – Neck • Lamina VI – Base – Proprioceptive : Laminae V – VI • Lamina VII – Intermediate grey matter • Lamina VIII – Medial part of Ant horn: Interneurons • Lamina IX – Lateral part of Ant horn: α & γ neurons • Lamina X – Around central canal: Substantia gelatinosa centralis

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