title: Origination of the muscular branches of the median nerve: an electrophysiological study.
abstract: BACKGROUND
  In lower brachial plexus injury, finger flexion after brachialis motor branch transfer is relatively weak. We sought to screen potential branches of the median nerve from the upper trunk for strengthening finger flexion in addition to the brachialis motor branch. However, the spinal origin of the muscular branches of the median nerve based on electrophysiological study was unclear.
  
  
  OBJECTIVE
  To determine the spinal origin of the muscular branches of the median nerve.
  
  
  METHODS
  An intraoperative electrophysiological study was carried out in 18 patients who underwent contralateral C7 nerve transfer. After exposure of the brachial plexus nerve roots on the healthy side, the amplitude of the compound muscle action potential of each median nerve-innervated muscle was recorded while the different nerve roots were stimulated.
  
  
  RESULTS
  The pronator teres received fibers from C5, C6, and C7. It had more contribution from C5 and C6 than from C7 (P<.05). The flexor carpi radialis was innervated mainly by C6 and C7. The nerve branches of the palmaris longus and flexor digitorum superficialis stemmed primarily from C7 and the lower trunk, and no significant difference was found between them (P>.05). The flexor digitorum profundus, flexor pollicis longus, pronator quadratus, and abductor pollicis brevis were innervated predominantly by the lower trunk (P<.05).
  
  
  CONCLUSIONS
  This electrophysiological study indicates that the pronator teres branch might be the most feasible alternative donor nerve to supplement the brachialis motor branch and strengthen finger flexion after lower brachial plexus injury.
authors.affiliation: Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai, People's Republic of China; Key Laboratory of Hand Reconstruction, Ministry of Health, Shanghai, People's Republic of China; and Shanghai Key Laboratory of Peripheral Nerve and Microsurgery, Shanghai, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Dong
authors.forename: Cheng-Gang
authors.initials: CG
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhu
authors.forename: Dong
authors.initials: D
authors.lastname: Tian
authors.forename: Yu-Dong
authors.initials: YD
authors.lastname: Gu
mesh_terms: D000200:Action Potentials; D000328:Adult; D001917:Brachial Plexus / Q000601:surgery; D020516:Brachial Plexus Neuropathies / Q000601:surgery; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000033:anatomy & histology* / Q000601:surgery; D018482:Muscle, Skeletal / Q000294:innervation; D016067:Nerve Transfer / Q000379:methods*; D034941:Upper Extremity / Q000294:innervation*