an instrument that displays and records a graphic tracing () of the minute voltage changes in muscle tissue, used in the diagnosis of muscle and nerve disorders: the tracing is made audible by connecting the voltage to a speaker
See electromyograph in American Heritage Dictionary 4
(ĭ-lĕkˌtrō-mīˈə-grăfˌ)
noun
An instrument used in the diagnosis of neuromuscular disorders that produces an audio or visual record of the electrical activity of a skeletal muscle by means of an electrode inserted into the muscle or placed on the skin.