electromyography (EMG)

(redirected from electromyography EMG)
Electromyogram (diagrammatic).

electromyography (EMG)

technique of recording electrical activity of muscle either percutaneously, with adhesive pad electrodes (more common but can only be applied to superficial muscles), or intramuscularly, through fine wires, usually of platinum, insulated except at their tips (records from a smaller domain within a muscle, but not necessarily a superficial one). EMG is used in both normal and pathophysiology to study the timing of muscle activation, as well as its extent, to which the resultant force generation is approximately proportionate. electromyogram the trace that is recorded. integrated EMG electronically processed modification of the direct signal from the electrodes. As muscle action potentials pass under the electrodes they will each go positive and negative by turns, making a 'biphasic' (AC) signal; to integrate this, the signal is first rectified and then smoothed with a time constant such that the trace produced looks similar in form to a mechanical record of the resulting contraction.