Origin:  C2-C4 roots, cervical plexus, spinal accessory nerve.

Recording Site:  Trapezius

Reference Site:  Shoulder

Ground:  Upper back

Stimulation Site:  Posterior neck

Procedure:  The recording electrode is placed on the belly of the trapezius muscle.  The reference electrode is placed on the top of the shoulder.  The nerve is stimulated at the neck, just lateral to the sternocleidomastoid muscle.