Origin:  C8 root, lower trunk and medial cord of the brachial plexus

Recording Site:  Top of hand

Reference Site:  Base of 5th finger

Ground:  Top of Hand

Stimulation Site:  Wrist

Procedure:  The recording electrode is placed on the dorsum of the hand at the bottom of the “V” web space located between the proximal fourth and fifth metacarpal bones.  The reference electrode is placed at the base of the 5th finger.  A distance of 8 cm is measured from the recording electrode to the wrist.  Stimulation occurs at the wrist in the space between the ulna and flexor carpi ulnaris tendon.  Additional stimulation sites include at the elbow by the ulnar groove.