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Muscle examination in the evaluation of weakness

Marc L Miller, MD
Section Editors
Ira N Targoff, MD
Jeremy M Shefner, MD, PhD
Deputy Editor
Monica Ramirez Curtis, MD, MPH


The evaluation of the patient presenting with a complaint of "weakness" involves three steps:

Distinguishing true muscle weakness from motor impairment due to fatigue, pain, or stiffness rather than loss of muscle power

Localizing the site of the lesion within the neuromuscular system that is producing weakness

Determining the cause of the lesion

The muscle examination is critical in the diagnostic evaluation of patients complaining of weakness or presenting with motor impairment. Together with the history and general physical examination, demonstrating the presence of true muscle weakness is the first step in this evaluation. Laboratory and electrophysiologic studies of nerves and muscles and muscle biopsy may then be required to complete the evaluation. Serial measurements of muscle strength and function are also necessary in the long-term follow-up of patients with neuromuscular disorders to determine response to treatment.

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Literature review current through: Nov 2017. | This topic last updated: Oct 11, 2017.
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