[168] Cross's _Surgery_, vol. ii. p. 273, 3d ed. [169] Miller's _System of Surgery_, p. 1339; Holmes's _Surgery_, vol. iii. p. 571. CHAPTER XIV. OPERATIONS ON NERVES. NERVE-STRETCHING.--Surgical literature in last ten years is full of cases in which nerves have been stretched for all manner of diseases with varying success: an example of the operative procedure may suffice:-- 1. Stretching of the great sciatic either for sciatica, sclerosis, or locomotor ataxia. _Operation._--A line drawn from the centre of the space between the tuberosity of the ischium or the great trochanter to a corresponding point between the condyles of the femur will give the direction. A free incision in this line three or four inches in length--the nerve lies just below the the femoral aponeurosis, beneath the edge of gluteal fold, requiring no muscular fibres to be divided. It must be raised from its bed and boldly stretched or elongated into a loop. Symington's experiments have shown that in the average adult 130 lb. are required to break the nerve. 2. The facial has been stretched for spasm. The trunk is easily reached by an incision extending from near the external auditory meatus to the angle of the jaw, which enables the parotid to be pushed forward and the edge of the sterno-mastoid pulled backwards. NEUROTOMY AND NEURECTOMY.--Chiefly performed for neuralgia of the fifth nerve. _a._ This is a very easy operation if directed at the terminal branches only of the nerve, where they make their exit from the frontal, supraorbital, and mental foramina. The author has done it in very numerous cases, and with great relief, if care be taken to destroy the nerve in the foramen to some extent--a sharp-pointed thermo-cautery does this easily and safely. _b._ The more severe and radical operation of cutting out a portion of the trunk of the fifth nerve just after it has left the skull, and destroying Meckel's ganglion, has been done pretty frequently, chiefly by American surgeons--in various ways. 1. _Carnochan's Operation._--Exposing the whole front wall of antrum, its cavity is opened into from the front by a large trephine. The lower wall of the infra-orbital canal is cut away by a chisel, the posterior wall of the antrum by a smaller trephine, the nerve thus isolated is traced up to and past Meckel's ganglion, which is removed close to the foramen rotundum by cutting the nerve by curved blunt-pointed scissors. 2. _Pancoast's Operation._--Expose the coronoid process by a free incision, divide it at its root and throw it up, then expose and tie internal maxillary artery, after which the upper portion of the external pterygoid is to be detached from the sphenoid, thus exposing the nerve leaving foramen ovale; the second portion is deeper and not so easily got at.