The compound muscle action potential (CMAP) or compound motor action potential is an
electromyography
Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyog ...
investigation (electrical study of muscle function).
The CMAP idealizes the summation of a group of almost simultaneous
action potentials from several
muscle fibers in the same area. These are usually evoked by stimulation of the
motor nerve. Patients that suffer from
critical illness myopathy, which is a frequent cause of weakness seen in patients in hospital
intensive care units, have prolonged compound muscle action potential.
References
Neurophysiology
Action potentials
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