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rector until the nerve is exposed. Excise an inch or more of the nerve.
The nerve is sometimes found between the sternal and clavicular fibers, but generally beneath this septum. Sometimes the nerve is beneath the whole muscle. By searching the posterior border of the muscle, the nerve can be found and followed back into the muscle. Provide drainage, and close the wound.
NERVE-STRETCHING OF THE GREAT SCIATIC.
Place the subject on the abdomen.
Begin an incision a little above the gluteal fold, and extend it downward four inches in the middle line of the thigh. Divide the integument and fasciæ, and expose the border of the gluteus-maximus muscle. Divide the cellular tissue along the outer border of the long head of the biceps femoris, and retract the sides of the wound. The nerve is seen resting on the adductor magnus. Separate the nerve with the fingers. Raise the leg from the table by pulling on the nerve hooked up by the fingers. If the limb is very heavy, it need not be quite raised. Provide for drainage, and close the wound.
NERVE-SUTURING OF THE MEDIAN.
Supinate the forearm.
Begin an incision about two inches above the wrist, between the tendons of the palmaris longus and the flexor carpi radialis. The incision should extend upward three inches, dividing the integument and fasciæ. Separate the tendons of the palmaris longus and the flexor carpi radialis, and raise the
flexor sublimis digitorum muscle. Retract the sides of the wound to expose the nerve. (Excise an inch of the nerve.)
Both ends of the nerve being exposed, should be stretched by means of forceps to approximate them. Freshen the ends of the nerve by cutting away the tips which were crushed by the forceps. Bring the ends into apposition by means of stitches extending through the nerve-sheath only. Provide for drainage, and close the wound.
OPERATIONS ON THE CIRCULATORY SYSTEM.
COMPRESSION OF VESSELS.
1. PRESSURE is applied to a particular vessel by various means, of which Petit's tourniquet will be considered.
Apply the tourniquet by encircling the limb with the strap, placing under the strap and over the vessel a compress. A roller-bandage will act as a compress, and should be placed so as to engage the vessel between it and the bone. The lumen of the vessel is closed by turning the screw of the tourniquet to tighten the strap
2. The soft tissues of a part may be compressed by various means, of which the elastic bandage and tubing are in most common use.
Apply the bandage spirally, overlapping each tumn to a very slight extent. The bandage must be stretched before the turn is applied.
If a limb is to be rendered bloodless, apply the bandage from the extremity toward the trunk. The last two or three turns of the bandage may be tied together, and the bandage removed from below, or the limb may be encircled by rubber tubing just above the bandage, when the bandage may be entirely removed.
At the shoulder the tubing must run under the axilla and over the clavicle.
At the groin the tubing must run between the anus and the tuber ischii of the side to be compressed, and over the middle of the crest of the ilium. It can be held above the ilium or secured to a belt or bandage encircling the body just above the crests of the ilia.
The tubing, like the bandage, must be stretched before the turns are applied to the part.
TORSION OF VESSELS.
A vessel of considerable size must be seized at its end by means of forceps and separated from the surrounding tissue to an extent to allow of being seized at a right angle to its course by a second pair of forceps. A quarter of an inch of the vessel should separate the forceps if the vessel is of large size. Turn the forceps holding the end of the vessel until but slight resistance is offered, after which the other pair of forceps are removed. The forceps holding the end of the vessel is last removed. On the cadaver the effect of the torsion can only be surmised.
Vessels of small size are caught by means of forceps, and twisted until their ends (and the little tis. sue always included in the bite of the forceps) separate from the cut surface.
LIGATURE OF VESSELS.
I. Ligature of a Divided Vessel.—Ligature of a severed vessel is performed by catching the end of the vessel by means of forceps, and then compressing the vessel in the loop of a knot.
If the vessel is large, it should be separated from surrounding tissues, and accurately ligatured.
When catgut is used, a third knot should be tied to insure against the loosening of the ligature.
If the vessel is of small size, some of the surrounding tissue is included in the loop of the knot.
Care must be exercised to prevent including the instrument in the loop of the knot. A tenaculum may be used to pick up the vessel and adjacent tissue, when, if the tissue is nicked for the ligature, it is not liable to slip.
The first knot should be drawn upon until, in the case of a large vessel, its inner coats are felt to crush. The second knot should never be drawn upon with great force, for the ligature is then very readily broken.
If a vessel is cut, but not severed, and the vessel be a large vein, the opening is pinched together by means of forceps, and the ligature applied as for a small vessel. The caliber of the vein is thus not occluded. In case of arteries, the section must be completed, and both ends treated with a ligature. On the cadaver a partially severed vessel is hardly noticed.
II. Ligature of a Vessel in its Continuity.—The position of a vessel is determined by certain“ guides":
1. The surface guide is a line drawn joining certain fixed points, as bony eminences.
2. The deep guides are the contiguous anatomical structures.
3. The feel and color of the vessel.
General Rules.—When the location is chosen, the incision is made usually in the surface guide, its