Electromyography of the perineal floor.

Electromyography is the study of minute potentials produced by the depolarization of the muscle membrane; they may be useful in the diagnosis of pelvic floor disorders. Either surface or needle electrodes may be used, depending on the type of information desired. Innervation deficits may be indicated by abnormal potentials observed in resting or active muscle. Electromyography is also useful in assessing coordination between bladder contraction and sphincter relaxation.