Origin:  C7 roots, middle trunk and lateral cord of the brachial plexus.

Recording Site: Ring Finger

Reference Site:  Ring Finger

Ground:  Palm or top of hand

Stimulation Site:  Wrist
 
Procedure:  The recording electrode is placed on the proximal phalanx of the ring finger.  The reference electrode is placed on the middle phalanx of the ring finger.  A distance of 13 cm is measured from G1 to the distal wrist crease over the median nerve.  The nerve is stimulated at the wrist, proximal to the wrist crease and between the flexor carpi radialis and palmaris longus tendons.  The nerve can also be stimulated at the elbow, above the elbow crease, medial to the pulse or biceps tendon. The nerve can also be stimulated at the elbow (above the elbow crease, medial to the brachial artery pulse or biceps tendon).

The same distance should be used when using the median ring finger study as a comparison study to the ulnar ring finger study.  This study can also be performed orthodromically.