Another way to tell the artery from the vein is to roll them lightly between the fingers. If it feels like a thin rubber tube, and does not roll together in a little bundle, the supposition is that the vessel is an artery. This however is not certain, as phlebitis, or some other diseased condition of the veins may result in the thickening of the walls of those vessels, to such an extent as to make it impossible to distinguish in this way between the artery and the vein.
The anatomical and the linear guides for the arteries and veins, and their relation to the accompanying nerve, will help also to tell them, one from the other.
How to Cut an Artery for Injection.
—After the artery has been located it should be freed from the surrounding tissues and then raised to the surface. After it has been raised to the surface the bone separator which is to act as a support while cutting the artery, should be placed underneath the artery.
The artery may be cut in several ways as follows—a T shaped incision may be made. This is a very old method, one of the first to be used for this purpose. To make this kind of an incision in the artery, the scalpel is placed point down about one-fourth the distance from the edge of the artery, and then by forcibly bearing down on the scalpel cut the artery crosswise. Rotating the artery the cut will now be on the upper surface. Now from the middle of the crosswise cut, extend a longitudinal cut lengthwise of the artery, for almost one half inch. We have no comment to make on this kind of an incision, excepting to say that the method is old and obsolete, and no longer used, and that a much better method is now used.
Another method suggested by some authors is the longitudinal incision. With the belly of the scalpel cut the artery lengthwise for a distance of a little less than one half inch. The disadvantage of this kind of a cut is that the operator does not know when he has cut to the center of the artery and no more than the center. If the cut has been made to a distance beyond the center, then the inside wall on the opposite side will be cut and if the wall is in the least diseased, the arterial tube when it is inserted may get between the walls which will mean that no fluid can be injected.
Another method is to cut the artery crosswise, placing the point of the knife on the artery about one fourth the distance from the edge of the artery, bearing down so that the point will come through to the bone separator which is beneath, then forcibly bearing down cut outward with the belly of the knife. Now rotate the artery and the cut will be on the front of the artery.
Another better method is the same as the above, but instead of cutting outward perpendicular to the artery, cut outward diagonally, then when the artery is rotated there will be a V—shaped cut. The point of the V should be made opposite the way the operator is to inject the fluid. With the aneurism hook, pick up the point of the V, which will mean that the hook will have to be inside of the artery, and using the hook as a guide insert the arterial tube. The only disadvantage of this method is that the tensil strength of the artery is to a certain extent weakened, but if the artery is not cut too deep, this is not a serious disadvantage. The advantage is that the operator is always certain that he is in the center of the artery, that if his knife is sharp, that he will always cut all three walls of the artery at once, and thus prevent a ruffling up of the inner wall of the artery should it be diseased.
The Injection of Fluid.
—One very important point to be taken into consideration when embalming, is the slowness with which the fluid should be injected.