Placement of electrodes for facial nerve monitoring using acceleromyography

Apparatus for objective monitoring of the orbicularis oculi (A) and the corrugator supercilii (B) muscle contraction using acceleromyography. An accelerometer is attached to the eyelid (A) or the eyebrow (B). Facial nerve stimulation (note that the negative electrode is distal to the positive electrode) will result in contraction of the eye muscles, which is measured by the accelerometer. The results are displayed on the monitor's screen.