THE PERIPHERAL NERVE STIMULATOR has achieved an accepted place in the practice of anaesthesia to monitor n e u r o m u s c u l a r function. Contraction of the fingers is usually elicited by placement of stimulating electrodes over the course of the ulnar nerve at the wrist or elbow. ~ H o w e v e r , transcutaneous stimulation of the ulnar nerve at the wrist is not always effective in eliciting muscle m o v e m e n t , particularly when surface electrodes are employed.The purpose of this c o m m u n i c a t i o n is to demonstrate how electrode placement as well as polarity of the nerve stimulator output can affect the performance of the peripheral nerve stimulator.