4-Corticospinal Tract Flashcards

1
Q

splits into what tracts

A

@ caudal medulla

  1. anterior corticospinal for cervical and upper thoracic levels
  2. lateral corticospinal for all spinal levels
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2
Q

pathway

A
  1. layer V of cortex/pyramidal
  2. corona radiata
  3. internal capsule (genu then posterior half of post limb)
  4. basis pedunculi of midbrain
  5. basal pons
  6. pyramid of medulla to decussate
  7. LMNs @ ventral horn
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3
Q

anterior CST functions in what

A

controlling axial muscles (neck, shoulder, upper trunk)

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4
Q

lateral CST functions in what

A

execution of distinct, skilled, well defined vol move of opposite side of body esp hand AND controls muscles of lower limb

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5
Q

lesion above decussation =

A

deficits contralateral to side of lesion

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6
Q

lesion below decussation =

A

deficits ipsilateral to side of lesion

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7
Q

UMN lesion signs

spastic paralysis

A
  1. initial/temporary muscle weakness (paresis) + flaccid paralysis + hypotonia + hyporeflexia
  2. regain function of proximal limb muscles, crude moves, fine moves of hand affected most
  3. shift to abnormal inc muscle tone (hypertonic) + severe hypertonicity/spasticity in distal limb muscles
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8
Q

why hypertonia in UMN lesion

A

UMN lesion damages more motor tracts than CST so descending inhibitory influences are eliminated
=overactive gamma motor neurons and hypertonia

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9
Q

extensor plantar response

babinski

A

if lesion of lateral CST then stroking plantar surface of foot = dorsiflexion of big toe + fanning of others

normal response is to plantar flex all 5

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10
Q

other UMN lesion signs

due to trauma or stroke

A
  1. hyperreflexia from overactive gamma motor neurons
  2. mild muscle atrophy
  3. babinski’s sign
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11
Q

LMN lesion signs

A

aka damage to neuron cell bodies or motor nerve to muscle
1. dec muscle strength
2. hypotonia
3. hyporeflexia or areflexia
4. flaccid paralysis
5. severe muscle atrophy
6. fibrillations/invol contractions
7. fasciculations/twitching

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12
Q

anterior cerebral A occlusion =

A

lesion in medial surface of M-I cortex
=motor deficits in contralatral leg and foot

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13
Q

middle cerebral A occlusion =

A

lesion in lateral surface of M-I cortex
=motor deficits in contralateral UL and face

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14
Q

lenticulostriate a occlusion =

A

motor deficits in contralateral side body

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15
Q

posterior cerebral A occlusion =

A

lesion in midbrain basis pedunculi
=motor def contralateral body

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