Before the advent of formaldehyde fluids the radial artery offered more advantages to the embalmer than any other artery used for injecting. But at the present time almost all embalming fluids contain large quantities of formaldehyde, and when injected into this artery, which is very small, it is liable to constrict the vessel to such an extent as to sometimes make it difficult to inject the fluid. Moreover, since both the radial and the ulnar arteries have many branches, a large quantity of fluid is liable to accumulate in the forearm, hardening it more than is necessary and giving the hand an undesirable color. The radial artery is very superficially located, and can be secured without the possibility of error and with very little mutilation. The expert will, of course, choose that vessel which he believes will at the time and under the circumstances best serve his purpose. _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.