Spinal Cord Function and Dysfunction

Question 1

what are the two enlargements of the spinal cord?

Answer 1

cervical- C3-T2, extra motor neurones go to muscles of upper back

lumbosacral- T11-L2 extra motor neurones for the muscles of the lower limbs

Question 2

what would be affected if the spinal cord is severed below the lumbosacral region?

Answer 2

bladder and bowel control

Question 3

what lesion would cause a loss of breathing ability?

Answer 3

C3-C5

Question 4

what is paraplegia?

Answer 4

loss of voluntary control of the lower limbs

Question 5

where is CSF sampled from?

Answer 5

the lumbar cistern

Question 6

how does the growth of spinal cord compare to the vertebral column?

Answer 6

spinal cord stop developing early whilst vertebral column continues growing into adulthood

Question 7

what are the three meningeal layers?

Answer 7

dura mater
arachnoid
pia mater

Question 8

where is CSF found in the meninges?

Answer 8

in the subarachnoid space

Question 9

what Pia mater protrusions tether the spinal cord?

Answer 9

denticulate ligaments

Question 10

what is contained in the extradural space between the dura and the cranium?

what can be done in this area?

Answer 10

venous plexuses and fatty tissues

this space can be used to inject anaesthetic

Question 11

name examples of tracts in the spinal cord

Answer 11

lateral corticospinal tract (motor) 
dorsal columns (sensory)
spinothalamic tract (sensory)

Question 12

what is the function of the lateral corticospinal tract?

Answer 12

fine movement

Question 13

what is the function of the dorsal columns?

Answer 13

touch, vibration, pressure

Question 14

what is the function of the spinothalamic tract?

Answer 14

pain and temperature

Question 15

what is the 2 stage response to injury of the lateral corticospinal tract?

Answer 15

1) spinal shock
- loss of all reflex activity below the lesion level
- flaccid paralysis (no muscular tone)

2) hyperreflexia (return of reflexes)
- reflexes are over exaggerated
- rigid paralysis (high muscle tone) as motor neurones are activated by a lower threshold

Question 16

what would cause a deficit on the same side as the lesion on the lateral corticospinal tract?

Answer 16

if the lesion is below the medulla where the crossing over (decussation) of the neurones occur.

Question 17

where do neurones of the dorsal column decussate?

Answer 17

level of the medulla

Question 18

where do neurones in the spinothalamic tract decussate?

Answer 18

dame level as the entry point of the sensory nerve into the spinal cord

Question 19

what is syringomyelia?

Answer 19

caused by enlargement of the central canal

Question 20

what are the characteristics of syringomyelia?

Answer 20

loss of temperature sensation in the arms but not the left due to the formation of the syrinx space in the spinal cord

Question 21

what is the effect of the syrinx space on the spinal cord?

Answer 21

selectively damages the spinothalamic axons that cross over at the level of the lesion but doesn’t affect the fibres that already cross it

Question 22

what are dermatomes and myotomes ?

Answer 22

derma- skin innervation (sensory, posterior root)

myo- muscle innervation (motor, anterior root)

Question 23

where do the fasciculus gracile and cuneatus come from?

Answer 23

gracile- lower body

cuneatus- upper body

Question 24

where are primary, secondary, tertiary neurones located?

Answer 24

primary on one side

secondary and tertiary on the other side due to decussation

Question 25

where is a lesion below t10 if there is loss of movement on the right side? what tract has been affected?

Answer 25

lesion on the right (ipsilateral)

corticospinal tract

Question 26

where is the lesion below t10 if there is loss of pain and temperature sensation on the right side?

Answer 26

lesion on the left (contralateral)

spinothalamic tract

Question 27

how can a seizure post-stroke be treated?

Answer 27

anti-convulsants:

Na+ channel blockers, GABAaR agonists, GABA-transaminase inhibitor.

Question 28

what is hemiparesis?

Answer 28

weakness of one entire side of the body

Hemiplegia is, in its most severe form, complete paralysis of half of the body.