Muscle examination in the evaluation of weakness
- Marc L Miller, MD
Marc L Miller, MD
- Clinical Assistant Professor of Medicine
- Tufts University School of Medicine
- Section Editors
- Ira N Targoff, MD
Ira N Targoff, MD
- Section Editor — Muscle Disease
- Professor of Medicine, Section of Rheumatology
- University of Oklahoma Health Sciences Center
- Jeremy M Shefner, MD, PhD
Jeremy M Shefner, MD, PhD
- Section Editor — Neuromuscular Disease
- Professor and Chair of Neurology, Barrow Neurological Institute
- Professor of Neurology, University of Arizona, Phoenix
- Clinical Professor of Neurology, Creighton University
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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