Detailed description of internal structure of spinal cord.

1. DR. MEHUL TANDEL

2. The Meninges

3. OBJECTIVES
• Three layers
• Subarachnoid space
• Cisternae
• Applied anatomy

4. The Meninges

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. The Meninges

7. DURA MATER
• Thick dense inelastic
membrane form outermost
covering of brain & spinal
cord
• Bilaminar:
• Endosteal layer
(outer)
• Meningeal layer
(inner)

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. duramater

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. Extradural Haematoma

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. Arachnoid
mater

14. Arachnoid Villi &
Granulation
Arachnoid
villi
Arachnoid
mater
Subarachnoid space
Arachnoid
granulations
Subdural space
Sites for CSF absorption

15. Subdural Space : Superior cerebral veins
beneath arachnoid

16. Subdural Haematoma
*
Dura
Arachnoid

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. Pia mater
Pia mater

19. Pia Mater
 Perivascular sheath:
Virchow – Robin’s
Space
 Over the cranial nerves &
fuses with their epineurium
 TELA CHOROIDAE:
 Choroid plexus:
 Forms CSF

20. Tela Choroidae & Choroid Plexus
Site of Formation of CSF

21. Subarachnoid Space

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. Median sagittal section to show the subarachnoid cisterns
& circulation of CSF
Superior
cistern(ambiens)
Interpeduncular
cistern
Cerebellomedullary
cistern
Chiasmatic
cistern
Pontine
cistern

25. Cisterna Interpeduncularis Lumbar Cisternae

26. *
Subarachnoid haemorrage
Dura
Arachnoid
Pia mater

27. SPINAL CORD

28. 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

29. EXTERNAL FETURES
• Cylindrical in shape
• Foramen magnum 
L1/L2 (adult)
L3 (newborn)
• Occupies upper ⅔ of
vertebral canal

32. Structure Of The Spinal Cord

33. External Features
Anterior median Fissure
Antero-lateral
sulcus
Antero-lateral
sulcus
Posterior median Sulcus
Postero-lateral
sulcus
Postero-
intermediate
sulcus

34. Ventral Grey
Horn
Lateral Horn
Dorsal Grey
Horn
Motor
Sensory
Autonomic
Grey Matter
Neurons,
Neuroglia
BV

35. Ventral Grey
Column
Intermediate
grey column
Dorsal Grey
Column

36. Head
Short & Broad
Ventral Grey Horn
Base

37. Dorsolateral
tract
Long & Narrow
Dorsal Grey Horn
Apex
Head
Neck
Base

38. Preganglionic-
Autonomic
Intermediate /
Lateral Grey Horn
T1 – L2 (Sympathetic)
S2 – S4 (Para-sympathetic)

39. Grey Commissure
Central part
Central Canal
Ventral Grey
Commissure
Dorsal Grey
Commissure
Crossing fibers

40. Anterior White
Funiculus
Lateral White
Funiculus
Posterior White
Funiculus
White Matter Nerve fibers, Neuroglia, BV
Fasciculus Gracilis
Fasciculus Cuneatus

42. • Neurons:
– Motor - α, β, γ
– Interneuron
• Axons pass through anterior nerve roots
as Final common pathway
Anterior grey columns

43. • 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

44. • Gamma(γ):
– Multipolar
– Golgi type 1
– Thinly myelinated
– Efferent – Intrafusal muscle fibres = Muscle Spindle
– Reflex control of muscle tone

45. • Beta(β):
– Multipolar
– Intermediate size
– Efferent – supply extrafusal & intrafusal fibres
• Interneuron:
– Multipolar
– Golgi Type II
– Confined within
grey matter
– Reflex activites
• Monosynaptic
• Polysynaptic

46. Nerve cells group in the Anterior gray
Columns
• 3 nerve cell groups
–Medial
–Lateral
–Central

47. • Medial:
–Entire spinal cord
–Subdivide:
Ventero-medial
Dorso-medial
Trunk

48. • Lateral:
– Cervical (C4 – T2) &
Lumbosacral enlargements (L2 – S3)
– Subdivide in to:
Arm & Thigh
Forearm & Leg
Hand & Foot
Ventero-lateral
Dorso-lateral
Retro-dorso-lateral

49. • Central
–Present in different regions
C3 – C5
Phrenic
C1 – C5
Spinal Accessory
Lumbosacral
L2 – S3

50. • Neurons:
– Interneuron
– Tract Cells
Posterior grey columns
• Interneuron:
– Reflex
– Receive terminals of
descending pathway
– Project to α, & γ
neuron

51. • 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

53. 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

54. Postero-marginal nucleus
Substantia gelatinosa
Nucleus proprius
Visceral afferent
nucleus
Nucleus dorsalis
(Clarke’s column)

55. • 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

56. • 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

57. • 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

58. • 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

59. • Visceral afferent nucleus
– Base - lateral to nucleus dorsalis
– T1 – L2/3, S2 – S4
– receives sensations from viscera

60. – 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

61. • Based on Connections, Cyto-architecture & Packing
density
• Total 10 Laminae
Laminar Concept – Rexed Laminae
X
IX
X - Substantia
Gelatinosa centralis

62. 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