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20 Cards in this Set
- Front
- Back
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* What are the three descending motor pathways?
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1. ventromedial brainstem pathway
2. lateral brainstem pathway (rubrospinal tract) 3. corticospinal pathway |
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What are the three tracts within the ventromedial pathway?
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1. Tectospinal tract (midbrain nuclei)
2. Reticulospinal tract (pons and medulla nuclei) 3. Vestibulospinal tract (medulla nuclei) "TRV" |
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* What is common for all pathways that originate above the pons? below?
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above pons --> pathway decussates
below --> no decussation |
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Where does the corticospinal tract decussate?
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medulla (pyramids)
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* Where is the nucleus of the rubrospinal tract?
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midbrain (above pons, so decussates), also decussates in midbrain
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where is the nucleus of the tectospinal tract? where does it decussate?
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midbrain; midbrain
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What is the nucleus of the rubrospinal tract? where is it located? what is another name for the rubrospinal tract?
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red nucleus
midbrain lateral brainstem pathway |
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At what level do you find the red nucleus?
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midbrain
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Where is the nucleus of the tectospinal tract?
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superior coliculus (midbrain)
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* How do the terminations of the descending pathways correlate to the muscles they innervate?
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more lateral terminations innervate distal muscles (e.g. hand) --> corticospinal tract and lateral brainstem pathway (rubro)
more medial --> proximal muscles (e.g. trunk) --> ventromedial brainstem pathway |
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Would you expect to see areflexia from an UMN of LMN injury?
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LMN
UMNs result in hyperreflexia, conus (after weeks, same immediate response) |
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Would damage to an UMN affect a single muscle or group?
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group
LMN more likely to only affect single muscle |
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Would an UMN or LMN injury result in more gross atrophy and loss of mass?
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LMN
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what is another term for long motor tracts?
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UMNs
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What does Babinski's sign test? what is the test?
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tests corticospinal tract (upper motor neurons / long motor tracts) lesions in CNS, especially demyelination
run probe along bottom of foot; normal = plantar flexion extension (toes up/fanning) is Babinski's sign --> lesion |
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what are the muscular signs of an UMN lesion?
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first hypotonia and hyporeflexia
after weeks: hypertonia, hyperreflexia |
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What are the three signs of spasticity?
Is this an UMN or LMN defect? |
hypertonia
hyperreflexia clonus (particularly in gastrocnemius) upper |
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Where is the lesion in decorticate rigidity?
what is the clinical sign? |
cerebral cortex lesion
arms FLEXED, legs EXTENDED (midbrain still in tact) Note: ventromedial brainstem pathway remains in tact |
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Where is the lesion in decerebrate rigidity?
what is the clinical sign? |
injury to the midbrain (loss of input from forebrain and upper midbrain)
arms & legs EXTENDED (injury to the midbrain) Note: ventromedial brainstem pathway remains in tact |
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Where is the lesion in "locked in" syndrome? what are the symptoms?
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No motor function, but spared sensation and cognition
Due to bilateral ventral pontine lesions (basilar artery distribution stroke, hemorrhage) that disrupt corticospinal and corticobulbar tracts; rare condition. Paralysis of all four limbs, no facial movements (c.n. VII, corticobulbar tr. destroyed), speech abolished (c.n. IX, X, XII) Patient remains conscious and often capable of vertical, but not horizontal (c.n. VI), eye movements--patient is “locked-into” his/her body |
