ABSTRACT
Electrophysiological study of muscles and their nerve supply is a well-proven method of analysis of disorders of the neuromuscular innervation. Electromyography (EMG) is a method for study of the electrical activity of voluntary, striated muscle at rest and during contraction. The motor nerve supply of muscles can be investigated by measuring the latency and amplitude of the evoked muscle response to electrical stimulation of the motor nerve. Two EMG techniques are in common use, concentric needle EMG and single fiber EMG (SFEMG). SFEMG is used in the evaluation of patients with fecal incontinence, urinary incontinence, and double incontinence. Transrectal stimulation of the pudendal nerve is achieved by using a disposable electrode array mounted on the examiner’s index finger. Women with stress incontinence of urine, or with genitourinary prolapse, show an increased fiber density in the external anal sphincter compared with age-matched control subjects, and similar abnormalities are found in concentric needle EMG studies.
