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14 Cards in this Set

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List two causes of spasticity, hypertonia, and hyperreflexia in the UMN.
1. Loss of cortical inhibition to:
- Rubrospinal tract
- Medial Reticulospinal tract

2. Loss of UMN control of Renshaw cells
Loss of Cortical control AND Cortical inhibition of BRAINSTEM CENTERS result in what symptoms and why?
Hypertonia

B/c of free release of excitation from brainstem centers to gamma motor neurons.
Extensor hypertonia of the lower extremity would indicate what?
Medial reticulospinal tract has lost cortical control due to lesion.
Flexor hypertonia of the upper extremity would indicate what?
Rubrospinal tract has lost cortical control due to lesion
What causes decorticate rigidity?
Bilateral damage to large portions of cerebral cortex and/or thalamus
What are the symptoms of decorticate rigidity?
Bilateral UMN spasticity
Coma
Hypertonia in flexor of UE
Hypertonia in extensors of LE
Which tracts are affected in decorticate rigidity?
Medial Reticulospinal tract
Rubrospinal tract
Vestibulospinal tract

All are uninhibited to continuously excite
What are the symptoms of decerebrate rigidity
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
What causes decerebrate rigidity?
Bilateral damage to rostral brainstem (midbrain)
What tracts are affected in decerebrate rigidity?
Rubrospinal inhibited

Medial reticulospinal uninhibited to freely excite

Vestibulospinal uninhibited to freely excite
In decorticate rigidity, flexion of the UE is caused by what tract?
Rubrospinal tract
In decorticate rigidity, extension of the LE is caused by what tract?
Medial reticulospinal tract

Lateral Vestibulospinal tract
In decerebrate rigidity, the extension of both UE and LE is caused by what tract?
Medial reticulospinal tract

Lateral Vestibulospinal tract
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