To the study of the neuromuscular system in peripheral nerve injuries, relatively insufficient thought is given, possibly because of the apparent crudeness of the problems involved. Yet in army hospital work we have found, in making decisions as to the operative and nonoperative treatment of nerve-wound patients, that motor symptoms have become our chief reliance. This is due to the fact that motor fibers are more vulnerable than sensory fibers, so that when mixed nerves are injured the earliest, and often the only, signs of trouble are presented by the motor fibers. Furthermore, from the patient's standpoint, motor defects are of much importance because of resulting disfigurement and inconvenience, and of the economic loss due to interference with work.
In dealing with peripheral nerve injuries the basal diagnostic fact on the motor side is that voluntary contractility in a muscle is proof that neural connection exists between it and its