electromyography

See electromyographic.

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Process of graphically recording the electrical activity of muscle, which normally generates an electric current only when contracting or when its nerve is stimulated.

Electrical impulses are shown as wavelike tracings on an oscilloscope and recorded as an electromyogram (EMG), usually along with audible signals. The EMG can show whether muscle weakness or wasting is due to nerve impairment (as in amyotrophic lateral sclerosis and poliomyelitis) or muscle impairment or disease (myopathy).

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      the process of graphically recording the electrical activity of muscle. Normal muscle is electrically silent when at rest, but when it is active, as during contraction or stimulation, an electrical current is generated, and the successive action potentials (impulses) can be registered on a cathode-ray oscilloscope screen in the form of continuous wavelike tracings. The visual recording, called an electromyogram, or EMG, is customarily accompanied by auditory monitoring with a loudspeaker. For diagnostic purposes, records of muscle electrical activity are usually obtained during muscle relaxation, during voluntary contraction when needle electrodes are inserted into the muscle under study, and during muscle activity evoked by the stimulation of its nerve. Weakness or wasting of muscle is generally caused either by impairment of the nerves supplying it (neuropathic disorders, such as amyotrophic lateral sclerosis and poliomyelitis) or by intrinsic muscle impairment or primary muscle disease (myopathy). In neuropathic disorders, there is usually increased spontaneous activity during muscle relaxation (fibrillation and fasciculation), together with reduced, altered, or absent normal muscle action potentials. In myopathies, there is frequently a reduction in the amplitude or duration of the muscle action potentials and an increase in the complexity of their wave form.

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Universalium. 2010.

Look at other dictionaries:

  • Electromyography — Not to be confused with Electronystagmography (ENG), Electrocardiography (ECG), or Electroencephalography (EEG). Electromyography Intervention ICD 9 CM 93.08 MeSH …   Wikipedia

  • electromyography — noun see electromyograph …   New Collegiate Dictionary

  • electromyography — noun A technique for evaluating and recording the activation signal of muscles. Syn: EMG See Also: electromyogram, electromyograph …   Wiktionary

  • electromyography — 1. The recording of electrical activity generated in muscle for diagnostic purposes; both surface and needle recording electrodes can be used, although characteristically the latter is employed, so that the procedure is also called needle… …   Medical dictionary

  • electromyography — n. production and study of electromyograms (graphic records of the electrical activity of muscles) …   English contemporary dictionary

  • electromyography — [ɪˌlɛktrə(ʊ)mʌɪ ɒgrəfi] noun the recording of the electrical activity of muscle tissue by means of electrodes. Derivatives electromyogram noun electromyograph noun electromyographic adjective electromyographically adverb …   English new terms dictionary

  • electromyography — n. continuous recording of the electrical activity of a muscle by means of electrodes inserted into the muscle fibres. The tracing is displayed on an oscilloscope. The technique is used for diagnosing various nerve and muscle disorders and… …   The new mediacal dictionary

  • electromyography — /əˌlɛktroʊmaɪˈɒgrəfi/ (say uh.lektrohmuy ogruhfee), /i / (say ee ) noun a method of investigating the action of muscles by tracking the electrical activity associated with this action, which makes use of electrodes either placed on the skin over… …   Australian English dictionary

  • electromyography — noun diagnosis of neuromuscular disorders with the use of an electromyograph (Freq. 1) • Hypernyms: ↑diagnostic procedure, ↑diagnostic technique …   Useful english dictionary

  • single fiber electromyography — (SFEMG) electromyography using a needle electrode to record the action potential of one muscle fiber at a time …   Medical dictionary

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