—The radial nerve lies to the outer side of the radial artery, three inches above the wrist. Should any of the nerves of the arm or forearm have been cut by an accident which has produced an incised wound they should be sought for in the wound if fresh, and in the neighborhood of the scar if older, and should be reunited by suture, as already described.
The Great Sciatic Nerve.
—In the lower extremity it is the great sciatic nerve which is usually made the subject of operation. An incision midway between the great trochanter and the tuberosity of the ischium, by which the lower border of the gluteus muscle is exposed, will enable the surgeon to identify the biceps, to divide the deep fascia, and find the sciatic nerve at the outer border of the muscle. It is sought for the purpose of nerve stretching, and it may be pulled completely out of the wound, while the entire weight of the limb may be suspended by it.
The Tibial Nerve.
—The tibial nerves may be exposed through incisions identical with those indicated for ligation of the tibial arteries.
The Anterior Crural Nerve.
—The anterior crural nerve lies in Scarpa’s triangle, near Poupart’s ligament, on the outer side of the femoral artery.
Tetanus should be treated by injecting antitoxin into the main nerve trunks, as well as into the spinal canal. The individual nerve trunks of the brachial plexus may be exposed in the upper arm, where the point of the hypodermic syringe needle may be inserted into their substance. The same expedient may be employed with the sciatic or anterior crural trunks, through the incisions just described. The same measures may be used in cocainizing the nerve trunks, as suggested by Crile and others, and described in the chapter on Alterations of Blood Pressure ([p. 181]).
Abbe has suggested to treat certain cases of inveterate neuralgia of the peripheral nerves by an intraspinal division of the posterior nerve roots.
There has been added to the standard operations on nerves another measure. This consists of grafting by means of foreign material; using a section of nerve trunk removed freshly from some animal, or inserting catgut loops between nerve ends which shall serve as trellises upon which the growing nerve tissue may arrange itself. Powers, of Denver, has, for instance, reported the implantation of four inches of the great sciatic nerve of a dog into the external popliteal of a man. The results seemed to be good so far as sensation was concerned, but negative as regards motion. Probably no method of nerve grafting will give so good results as the utilization of a part of the nerve itself to be operated upon, by partially detaching and turning back a portion of its central end and uniting it to a similar flap made from the other end. Various operators have made use of different materials for the purpose of forming a tube around the nerve ends, and thus excluding other tissues. For this purpose cargile membrane is perhaps as serviceable as any. When all other measures fail the method by long catgut sutures may be adopted.