The muscle fibers of a normal voluntary muscle produce electric discharges which are recorded as a compound action potential from the extracellular space. The quantitative and qualitative analyses of these action potentials and their deviations from normal are assessed during electromyography.Historically, Adrian and Bronk, using a concentric-needle electrode, first recorded muscle action potentials in 1929.1 The development of the cathode ray oscilloscope and the improvements in amplifying systems have since made it possible to view and obtain records of the action potentials of voluntary muscle under a variety of conditions. Application of physiological techniques and principles, notably by Buchthal,2,3 has enhanced the knowledge and understanding of the changes recorded by electromyography in various pathological states of muscle and nerve.
Material and Methods
The electromyographic findings in 159 patients with neuromuscular disorders investigated at the Clinical Center of the National Institutes of Health are summarized. In all
HUMPHREY JG, SHY GM. Diagnostic ElectromyographyClinical and Pathological Correlation in Neuromuscular Disorders. Arch Neurol. 1962;6(5):339–352. doi:10.1001/archneur.1962.00450230001001
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