UMN signs

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Upper motor neurone signs are the result of an interruption in the neural pathway above the anterior horn cell.

Characteristic of an upper motor neurone disease are:

  • weakness - the extensors are weaker than the flexors in the arms, but the reverse is true in the legs
  • muscle wasting is absent or slight - muscle wasting is prominent in a lower motor neurone lesion
  • hyper-reflexia and clonus - reflexes are absent or reduced in a lower motor neurone lesion
  • spasticity
  • no fasciculations - fasciculations occur in a lower motor neurone lesion
  • extensor plantar responses

Last reviewed 01/2018

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