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14 Cards in this Set
- Front
- Back
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List two causes of spasticity, hypertonia, and hyperreflexia in the UMN.
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1. Loss of cortical inhibition to:
- Rubrospinal tract - Medial Reticulospinal tract 2. Loss of UMN control of Renshaw cells |
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Loss of Cortical control AND Cortical inhibition of BRAINSTEM CENTERS result in what symptoms and why?
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Hypertonia
B/c of free release of excitation from brainstem centers to gamma motor neurons. |
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Extensor hypertonia of the lower extremity would indicate what?
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Medial reticulospinal tract has lost cortical control due to lesion.
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Flexor hypertonia of the upper extremity would indicate what?
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Rubrospinal tract has lost cortical control due to lesion
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What causes decorticate rigidity?
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Bilateral damage to large portions of cerebral cortex and/or thalamus
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What are the symptoms of decorticate rigidity?
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Bilateral UMN spasticity
Coma Hypertonia in flexor of UE Hypertonia in extensors of LE |
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Which tracts are affected in decorticate rigidity?
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Medial Reticulospinal tract
Rubrospinal tract Vestibulospinal tract All are uninhibited to continuously excite |
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What are the symptoms of decerebrate rigidity
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1. Bilateral UMN spasticity
2. Coma 3. Hypertonia in extenosrs of neck and proximal extensors of UE 4. Hypertonia in extensors LE 5. Medial rotation of UE |
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What causes decerebrate rigidity?
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Bilateral damage to rostral brainstem (midbrain)
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What tracts are affected in decerebrate rigidity?
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Rubrospinal inhibited
Medial reticulospinal uninhibited to freely excite Vestibulospinal uninhibited to freely excite |
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In decorticate rigidity, flexion of the UE is caused by what tract?
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Rubrospinal tract
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In decorticate rigidity, extension of the LE is caused by what tract?
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Medial reticulospinal tract
Lateral Vestibulospinal tract |
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In decerebrate rigidity, the extension of both UE and LE is caused by what tract?
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Medial reticulospinal tract
Lateral Vestibulospinal tract |
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Describe the lesion location for the following alternating hemiplegia:
- Superior alternating hemiplegia - Middle alternating hemiplegia - Inferior alternating hemiplegia |
CN III & Pyramidal tract
CN VI & Pyramidal tract CN XII & Pyramidal tract |
