Abstract: An EMG monitoring system includes a matrix of detection electrode arrays that is positioned on the patient along his or her spine. The arrays are electrically connected through a switching mechanism to EMG amplifiers that are included in conventional monitoring instrumentation. A switch controller operates the switches to provide signals to the EMG amplifiers from selected sets of detection electrode arrays. The controller controls the switches to provide signals simultaneously to each EMG amplifier. If the monitoring instrumentation includes four EMG amplifiers, the matrix of electrode arrays and the switching mechanism may be used to take simultaneous measurements at two different spinal levels. If additional EMG amplifiers are included, simultaneous measurements at additional spinal levels may also be made. The matrix may also include redundant arrays and/or electrodes, such that the clinician can select the sets of electrodes that conform to the size of the patient.