muscle wasting

Last reviewed 01/2018

Muscle wasting is the loss of muscle bulk due to:

  • reduced neuronal stimulation of the muscle
  • primary muscle disease:
    • muscular dystrophy
    • myopathy
    • myositis

Reduced neuronal stimulation of the muscle may be due to:

  • a lesion of the peripheral nerve or the neuromuscular junction:
    • often referred to as a "lower motor neurone" lesion
    • when there is a progressive lesion of a motor nerve, wasting only occurs when collateral sprouting from surviving neurones is not sufficient to preserve muscle function
    • EMG will detect a motor unit potential abnormality
  • disuse atrophy:
    • often occurs around a painful joint
    • EMG is usually normal
  • parietal atrophy:
    • due to stroke
    • EMG is usually normal