Origin:  C6-C7 roots, upper or middle trunk and posterior cord of the brachial plexus, radial nerve

Recording Site:  Base of the FDI web space between the index finger and thumb

Reference Site:  Base of thumb

Ground:  Palm or top of hand

Stimulation Site:  Radius bone of forearm

Procedure:  The recording electrode is placed on the base of the FDII web space between the index finger and thumb, at the point where the bones are connected.  The reference electrode is placed on proximal phalanx at the base of the thumb.  A distance of 10 cm is measured from G1 straight back over the radius bone in the forearm.  The nerve is stimulated in the forearm by the radius bone.