spinal cord function and dysfunction

Question 1

what are the 2 enlargements of spinal cord?

Answer 1

• cervical: C3-T2: has extra motor neurones that go to muscles of upper back
• lumbosacral enlargment: T11-L2: extra motor neurones that go to muscles of lower limbs

Question 2

what is paraplegia?

Answer 2

loss of voluntary control of lower limbs

Question 3

what are denticulate ligaments?

Answer 3

small protrusions of pia mater that tether spinal cord

Question 4

what is extradural space?

Answer 4

• unique extradural space
• b/ outside of dura and bone
• full of venous plexuses and fatty tissue
• used to inject anesthetic

Question 5

what is the lateral corticospinal tract?

Answer 5

• motor
• important for fine movement
• neurones here decussate at level of medulla

Question 6

what does injury to the lateral corticospinal tract result in?

Answer 6

2 stage response:

1. spinal shock: lose all reflex activity below level of lesion, flaccid paralysis
2. return of reflexes: hyperreflexia, reflexes over exaggerated, rigid paralysis

Question 7

what is the dorsal column?

Answer 7

• sensory
• tough, vibration, pressure
• neurones here decussate at medulla

Question 8

what is the spinothalamic tract?

Answer 8

• sensory
• pain and temp
• neurones decussate at same level as entry point of sensory nerve

Question 9

what is syringomyelia?

Answer 9

• enlargement of central canal
• characterised by: loss of temp sensation in arms but not legs
• formation of a space in spinal cord = syrinx
• large space selectively damages spinothalamic axons that cross over at level of lesion
• doesn’t affect fibres that have already crossed over