Interscalene brachial plexus blockade does not guarantee complete C8-T1 root block.

Dear editor, After carefully reading the recent paper by Gu et al, 1 a few questions and concerns arose. In the Background it is mentioned that " LI4 is supplied by the median nerve ". 1 No reference is given to support this statement. Also, it is stated that determination of electroacupuncture (EA) intensity " was generally accompanied by mild muscle contraction in the index finger ". 1 According to Anatomy for Acupuncture by Dorsher and Cummings (http:// www.anatomy.tv/atv2/mainwindow. aspx?ref=0&titleid=26&svrid=0& App=acupuncture), sensation from the skin of the first dorsal web space is conveyed by the terminal radial nerve, and the muscles most often needled at this point are the first dorsal interosseous and adductor pollicis brevis, both of which are innervated by the ulnar nerve (myotome C8-T1). Deep needling closer to the first metacar-pal bone may penetrate flexor polli-cis brevis, which is innervated by the ulnar and median nerves (myotome C8-T1), but this is not usually achieved with needling to 1.25 cm depth at LI4. If the needle were to have been directed ven-trally to the second metacarpal bone (in the direction of SI3, on the ulnar border of the hand at the level of the palmar crease), the needle might have reached the first lumbrical, which is also innervated by the median nerve. 2 In this case, flexion of the metacarpophalangeal joint with extension of the inter-phalangeal joints of the second finger would have been elicited with EA. When describing the movement of the index finger or forefinger when performing EA at LI4, it should have been mentioned whether there was abduction of the index finger, adduction of the thumb, or both, reflecting stimulation of the first dorsal interosseous, the adductor pollicis brevis, or both. If flexion of the metacarpo-phalangeal and carpometacarpal joints of the thumb was elicited, the needle would likely have been placed in the flexor pollicis brevis. Flexion of the metacarpophalangeal joint with extension at the inter-phalangeal joints of the second finger would indicate needling of the first lumbrical. Stating the direction of insertion or, even better, identification of movement during EA, would have identified which muscle(s) the needle had reached and which nerves were being stimulated. 2 In the description of the experimental EA protocol, several aspects require elucidation. It is stated that a " continuous rectangular waveform (pulse width 30 ms) at a frequency of 4 Hz " 1 was applied. The polarity of …