Spinal Cord & Spinal Nerves

Question 1

Protective structures

Answer 1

• surrounding and protecting spinal cord
  
  • vertebrae
  • spinal meninges
  • CSF

Question 2

Spinal Cord Protection

Answer 2

• vertebrae and spinal canal
• epidural space filled with fat and blood vessels
• meninges
• spinal cord and dorsal ventral roots

Question 3

Spinal Meninges covering the spinal cord

Answer 3

• dura mater: dense irregular CT tube
• subdural space: filled with interstitial fluid
• arachnoid: spider web of collagen fibres
• subarachnoid space: CSF
• Pia mater: thing layers cover BV, denticulate ligaments hold in place

Question 4

External anatomy of spinal cord

Answer 4

• flattened cylinder
• in adults ends at approximately L1-L2
• consists of 31 pairs of spinal nerves
• cervical enlargement (upper limbs)
• lumbar enlargement (lower limbs)

Question 5

Spinal Nerves and Plexuses

Answer 5

-31 pairs of spinal nerves
-names and numbered by the cord level of their origin
8 pairs of cervical nerves C1-C8
12 pairs of thoracic nerves T1-T12
5 pairs of lumbar nerves L1-L5
5 pairs of sacral nerves S1-S5
1 pair of coccygeal nerves
-mixed sensory and motor nerves

Question 6

Inferior end of spinal cord

Answer 6

• conus medullaris
  
  • cone shaped end of spinal cord
• film terminale
  
  • thread like extension of pia mater
  • stabilizes spinal cord in canal
• caude equina (horse’s tail)
  
  • dorsal and ventral roots of lowest spinal nerves

Question 7

Lumbar puncture

Answer 7

• a need inserted into the subarachnoid space to withdraw cerebrospinal fluid
• spinal cord ends at L2, but subarachnoid space ends at S2
• spinal tap performed between L3 and L4 or L4 and L5 because this regions provides safe access to subarachnoid space without the risk of damaging spinal cord

Question 8

Grey matter of spinal cord

Answer 8

• shaped like a butterfly
• contains neuron cell bodies, unmyelinated axons, and dendrites
• dorsal gray horn: sensory neurons
• ventral gray horn: motor neurons
• lateral horns: autonomic neurons
• central canal continuous with 4th ventricle of brain
• contains CSF

Question 9

White matter of spinal cord

Answer 9

• surrounds gray matter

- anterior, lateral, and posterior white columns contain axons that form ascending and descending tracts

Question 10

Spinal cord and spinal nerves

Answer 10

• spinal nerves begin as roots
• dorsal or posterior root is incoming sensory fibres
  
  • dorsal root ganglion (swelling): cell bodies of sensory neurons

Question 11

Branches of Spinal nerves

Answer 11

• spinal nerve is mixed (sensory and motor) so as its branches:
  
  • anaterior primary Ramus and posterior primary Ramus

Question 12

Plexuses

Answer 12

-networks formed by joining of axons from anterior rami of adjacent nerves