Studies on conversion of motor function in intercostal nerves crossing for complete brachial plexus injuries of root avulsion type.

The progress of the functional conversion in cases where the 3rd and 4th intercostal nerves were crossed to the musculocutaneous nerve to regain elbow flexion after a total avulsion type of brachial plexus injury was followed up by means of the electromyogram, goniogram and spirogram in 25 patients. The joint position sense was further studied. It was found that in the early stage of reinnervation, spontaneous activity which synchronized with respiration was found in the biceps brachii muscles, but this involuntary element disappeared gradually and followed this the volitional control and endurance improved and became quite satisfactory within several years. It was observed that skin sensation played an important role in judging joint position.