Patterns of neuromuscular activity following tendon transfer in the upper limb: a preliminary study

Early results of a continuing study of the electrical activity of muscles after transfer, with an integrated system of electromyographic and video tape recording, recorded motions of the simple voluntary type, mostly with isometric contractions. A triceps-to-biceps transfer showed activity in the new motion one day after operation. A partial transfer of the pectoralis major (Clark) demonstrated isolated activity of the transfer after one year. A superficialis transfer to clawed ring and little fingers functioned to flex the metacarpophalangeal joints and to extend the interphalangeal joints. Transfer of superficialis to finger extensors showed that antagonists acted to provide unresisted extension. The original phasic activity of a muscle was retained in a study of extensor indicis proprius to thumb for opposition. New phasic activity was shown in transfer of extensor carpi radialis longus to digital flexors. In two instances of transfer of spastic wrist flexors to wrist extensors, the original phasic activity was retained, but in only one was the function assumed by the transfer even though wrist extension was improved.