Peripheral Nerve Surgery—Diagnostic Considerations

Abstract

T HE DIAGNOSIS of peripheral nerve lesions depends primarily on a precise knowledge of the regional anatomy. The surgical anatomy of the extremities does not receive the attention in teaching of medical students and internes that its importance deserves. The writer has received the impression from years of teaching medical students and resident staff officers that there is a regrettable lack of knowledge not only as to the function of peripheral nerves but as to their physical appearance and anatomy. Interne assistants frequently express surprise that the median or ulnar nerve when exposed by operation at the wrist is so large. They have been under the impression that the nerves are more or less minute structures and difficult to recognize. Fortunately, there has been a t rend in recent years toward better surgical training in conditions affecting the extremities but much remains to be done in this direction. Study of nerve lesions by clinical and experimental methods shows great activity during times of war but if one may judge by the American literature in the interval between the First World War and the present conflict there is little evidence of a sustained interest in these important injuries. I t is true that some valuable contributions, such as those of Stookey, Davis and Pollock, appeared in the interval between the two World Wars but on the whole the subject was rather generally neglected and this in spite of the fact tha t nerve lesions produced by industrial and transportat ion accidents in civilian life are by no means uncommon. They are easy to recognize but too often inadequately treated. The clinical examination of the patient supplies the most important information as to peripheral nerve injuries. Clinical diagnosis, however, has received many accessions from careful experimental investigation. I t is the purpose of this paper to discuss primarily the clinical diagnosis of peripheral nerve lesions, with brief reference to certain research methods as have proven helpful in advancing clinical diagnosis. There are definite effects which follow a lesion of every peripheral nerve. The interpretation of these effects in a given case requires precise knowledge of the motor distribution of the nerve as well as its cutaneous sensory supply. While there are numerous effects of division of a large peripheral nerve, loss of motor power in the muscles supplied by the nerve and associated loss of sensation are by far the most serious results.