Amussat's operation. — A transverse incision should be made an inch above the posterior part of the crest of the ilium, beginning at the external border of the erector spinæ, and extending outwards for three or four inches; the skin and superficial fascia being divided, the latissimus dorsi, and perhaps a portion of the external oblique muscle, will come into view: these, together with the fascia of the internal oblique and transversalis, should be divided on the director, and the loose subperitoneal tissue will be reached; in this, search for the intestine with the point of the director, and having found it, draw it out of the wound to a small extent; its edges being transfixed by sutures and united to the integuments, it may be opened at its most prominent part, and the operation will be complete.

The ascending colon may be exposed by an incision made in the right loin, in the same manner as described above. To open the cæcum, a wound should be made in the abdominal wall about three inches in extent, commencing an inch above the right anterior superior spine of the ilium, and extending downwards in the direction of Poupart's ligament.

CHAP. III.

TENOTOMY.

Tenotomy.-General Remarks.-Operation for Strabismus.-Division of the Sterno Mastoid, Tibialis Anticus, Hamstring Tendons, Tendo Achillis, Tiabilis Posticus.

TENOTOMY is an operation which in all practicable cases must be performed subcutaneously; it is with this object that a series of knives have been invented, allowing of the division of tendons with but little exposure of the wound to the external air.

The only instruments required for the performance of the following operations, with the exception of that for strabismus, are a sharp-pointed and a blunt-pointed tenotomy knife. The former is used for perforating the skin over tendons, and for dividing tendons themselves where there are no important parts within reach of injury. This knife is held as a pen; it should penetrate the skin on the flat, that is with the flat of the blade parallel to the line of the tendon. When in contact with the tendon, its edge should be turned at right angles to the former, and in this position the tendon should be divided. The blunt-pointed knife is for dividing tendons, such as those of the tibial muscles, where there are important parts in the neighbourhood which are exposed to injury; it is held in the hand and used in the same manner as the sharp-pointed knife.

In dividing a tendon, the end of the thumb should be

*Page 4, fig. 1.

placed over it while the knife is beneath it. In this manner the operator can ascertain when the division of the tendon is nearly completed, and can thus exercise greater care to guard the skin from injury as the knife approaches the surface.

The duties of an assistant in this operation are, firstly, to put the tendon on the stretch, to enable the operator to ascertain its exact position; secondly, to relax it, allowing of the insertion and adjustment of the knife; thirdly, to tighten the tendon while the operator divides it. The completion of the section can be ascertained by the sudden relaxation of the parts, by the creaking of the tendinous fibres under the knife, and often by the obvious gap remaining in the course of the tendon from the retraction of its ends.

The following operations should be undertaken while the body is yet fresh, either before or immediately after the operations on the arteries.

Division of the internal rectus muscle of the eye. - We have selected this muscle for the description of the operation for strabismus, as its division represents the proceeding usually required in that affection.

A spring-wire speculum, a pair of blunt-pointed small scissors, two pair of forceps, the one broad-pointed for holding the eye, the other being ordinary dissecting forceps, and a blunt hook, comprise the list of instruments necessary for the operation.

The operator should stand facing the subject, and the assistant behind the head, facing the operator. Having introduced the wire speculum between the lids, the assistant should, with the broad-pointed forceps, grasp a fold of the conjunctiva on the outer aspect of the eye and rotate the ball outwards so as to expose the inner part of the white of the eye. Let the operator now pinch up with the

forceps the conjunctiva, about one-third of an inch to the inner side of the cornea, and below the situation of the tendon of the inner rectus muscle; this fold of conjunctiva should be divided to the extent of about a quarter of an inch, in a direction radiating from the circumference of the cornea, and parallel with the lower border of the rectus. Having cut through the subconjunctival tissue in the same direction, pass the blunt hook into the wound, gliding its extremity on the eyeball, downwards, backwards, and lastly upwards, so as to pass beneath the lower border of the tendon of the rectus. Lift the tendon upwards, away from the ball of the eye, and pass the scissors down the hook into the wound, and divide the tendon beneath the conjunctiva by a series of snips, cutting from below upwards. The hook may be again inserted, and any remaining fibres caught up and divided in a similar manner.

The difficulty in this operation is to pass the point of the hook beneath the lower border of the muscle; this may be obviated by passing the hook some distance backwards before attempting to catch the tendon.

The foregoing proceeding may be applied to any of the recti muscles of the eye; the incision in the conjunctiva being made in each case, in a direction radiating from the circumference of the cornea.

Division of the sterno mastoid.-This operation is undertaken for the cure of certain cases of wry neck, and is generally put in practice on the lower third of the muscle, which at this part is covered by the skin, platysma, cervical fascia, and its own sheath; it is crossed obliquely from within outwards and above downwards by the external jugular vein, though generally at a point higher in the neck than that selected for its division. The operation may be performed in two ways; for the first method, a

deeply grooved director, a narrow, probe-pointed, curved bistoury, and a small scalpel are required. The operator should stand, in dividing the muscle of the right side, facing the subject and on the same side of the body as that of the muscle which he is about to operate upon. The assistant should hold the head in such a position as will render the muscle tense.

Let an incision be made with the scalpel on the anterior border of the sterno mastoid in its lower third, and extending down to the muscular fibres: this wound should be sufficiently large to admit the point of the grooved director. Pass the director into the wound, and turning it round the border of the muscle, push it with a semirotatory movement from within outwards under its deeper surface, until the point can be felt in the neck, beyond the outer border of the muscle. The director may now be entrusted to the assistant, and a bistoury be carefully pushed along the groove to its extremity. Divide the muscle from its outer to its inner border, and from its deeper to its more superficial surface; keeping the fingers of the left hand over the skin of the part, to ascertain when the muscle is completely divided, and to guard against the possibility of the bistoury cutting its way through the integuments.

The more usual, but perhaps less safe method of dividing the mastoid is practised in the following manner: A sharp and a blunt-pointed tenotomy knife being procured, an incision is made down to the anterior border of the muscle; through this the blunt-pointed straight knife is introduced on the flat, and carefully passed in the same position behind the muscle; its edge being turned towards the muscular fibres, they are divided in the same manner and with the same precautions as were recommended in the preceding operation. Great care must be exercised in passing the knife or director, as the case may be, to keep it close to