Functional motor innervation of brachial plexus roots. An intraoperative electrophysiological study.

The electrophysiological properties of the normal brachial plexus and functional motor innervation were examined during the operation of transfer of contralateral C7 transfer from the healthy side. Different roots of the brachial plexus were stimulated and maximum amplitudes were recorded. The results showed that functional motor innervation of brachial plexus roots were: C5 mainly forms the axillary nerve to innervate the deltoid muscle; C6 mainly forms the musculocutaneous nerve to innervate biceps; C7 mainly forms the radial nerve to innervate triceps; C8 mainly forms the median nerve to innervate flexor digitorum superficialis and profundus; and T1 mainly forms the ulnar nerve to innervate the intrinsic muscles of the hand.