Spinal Cord Function and Dysfunction Flashcards
what are the two enlargements of the spinal cord?
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
what would be affected if the spinal cord is severed below the lumbosacral region?
bladder and bowel control
what lesion would cause a loss of breathing ability?
C3-C5
what is paraplegia?
loss of voluntary control of the lower limbs
where is CSF sampled from?
the lumbar cistern
how does the growth of spinal cord compare to the vertebral column?
spinal cord stop developing early whilst vertebral column continues growing into adulthood
what are the three meningeal layers?
dura mater
arachnoid
pia mater
where is CSF found in the meninges?
in the subarachnoid space
what Pia mater protrusions tether the spinal cord?
denticulate ligaments
what is contained in the extradural space between the dura and the cranium?
what can be done in this area?
venous plexuses and fatty tissues
this space can be used to inject anaesthetic
name examples of tracts in the spinal cord
lateral corticospinal tract (motor) dorsal columns (sensory) spinothalamic tract (sensory)
what is the function of the lateral corticospinal tract?
fine movement
what is the function of the dorsal columns?
touch, vibration, pressure
what is the function of the spinothalamic tract?
pain and temperature
what is the 2 stage response to injury of the lateral corticospinal tract?
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
what would cause a deficit on the same side as the lesion on the lateral corticospinal tract?
if the lesion is below the medulla where the crossing over (decussation) of the neurones occur.
where do neurones of the dorsal column decussate?
level of the medulla
where do neurones in the spinothalamic tract decussate?
dame level as the entry point of the sensory nerve into the spinal cord
what is syringomyelia?
caused by enlargement of the central canal
what are the characteristics of syringomyelia?
loss of temperature sensation in the arms but not the left due to the formation of the syrinx space in the spinal cord
what is the effect of the syrinx space on the spinal cord?
selectively damages the spinothalamic axons that cross over at the level of the lesion but doesn’t affect the fibres that already cross it
what are dermatomes and myotomes ?
derma- skin innervation (sensory, posterior root)
myo- muscle innervation (motor, anterior root)
where do the fasciculus gracile and cuneatus come from?
gracile- lower body
cuneatus- upper body
where are primary, secondary, tertiary neurones located?
primary on one side
secondary and tertiary on the other side due to decussation
