_The Linear Guide._—Is a line drawn from the center of the bend of the elbow to the center of the ball of the thumb.
[Illustration: FIG. 49—The radial and ulnar arteries. (Gray)]
_The anatomical guide_ for the radial artery (in the wrist, where it should be raised) is the brachio-radialis muscle on the outside of the artery and the flexor carpi radialis muscle on the inside of the artery.
When about to raise this vessel, the embalmer should hold the arm at right angles with the body, with the palm up, and holding the hand of the body, with the hand, draw the arm tight. In most bodies this will show plainly the tendons of the muscles between which the vessel lies, thus affording an excellent guide for the incision. The arm should never be grasped and the tissues drawn out of their normal position, as that is very misleading. The vessel should be raised at a point about three inches above the wrist joint (the space where you would feel the pulse beat in life). The operator making an incision through the skin, superficial fascia, and fat, about one-half inch in length, will plainly see the artery lying in its sheath between the two tendons of the muscles. The cut should now be opened carefully, by placing the fingers on either side of it, and the fascia dissected from the artery, when it can easily be raised with the aneurism hook. There is no other vessel at this point that can be mistaken for the radial artery. Its two venae comites, or accompanying veins, are usually attached to the artery and need not be removed, as they are very small and can give the embalmer no trouble.
=How to Locate, Raise and Inject the Ulnar Artery.=—The ulnar is the larger branch of the brachial artery. It crosses obliquely the inner side of the forearm, to the beginning of its lower half, it then runs along the ulnar border to the wrist, crosses the annular ligament on the radial side of the pisiform bone (wrist bone), and immediately beyond this bone into two branches, the superficial and deep palmar arch. In its upper half it is deeply seated, being covered by all the surface muscles. It is crossed by the median nerve, which lies to the inner side for about an inch. In the lower half of the forearm the artery runs more superficially, and is covered only by the skin and superficial and deep fascia, but at that, the ulnar lies a little deeper in the wrist than the radial. The ulnar nerve lies to the inner side in the lower half and the ulnar artery is accompanied by two ulnar veins, one on either side, called the venae comites.