_Note._--As in the lower limb at page 24, and for the same reasons, I here insert a brief account of the methods of tying the ulnar and radial arteries. 1. LIGATURE OF ULNAR.--Only admissible in the lower half of its course. _Operation._--Use the tendon of the flexor carpi ulnaris as a guide, and make an incision along its radial edge, at least two inches in length; expose the deep fascia of the arm and then cautiously divide it; then bending the hand, the flexor carpi ulnaris is relaxed, and the artery is found lying pretty deeply between it and the flexor sublimis digitorum. The ulnar nerve lies at its ulnar side, and the venæ comites accompany the artery. In a tolerably muscular arm, the incision will have to be about an inch inside of the ulnar border of the limb. 2. RADIAL.--This artery lies more superficial than the preceding, and may be tied at any part of its course. _A._ Operation in upper part of fore-arm. Here the artery lies in the interval between the supinator longus and the pronator radii teres. In a muscular arm, the edge of the former muscle is the best guide; in a fat one, the incision may be made in a line extending from the centre of the bend of the arm to the inner edge of the styloid process of the radius. The deep fascia must be exposed and opened, and the muscles relaxed and held aside. The radial nerve lies on the radial side of the vessel. _B._ Operation in lower half of arm. Here the vessel is more superficial, lying in the groove between the flexor carpi radialis and supinator longus. An incision two inches in length, and parallel with these tendons, easily exposes the artery. The nerve is still on its radial side. _C._ Operation at first metacarpal. The artery may be tied easily enough in the triangular space bounded by the extensors of the thumb, on the dorsum of the proximal end of the first metacarpal bone. Skey[22] recommends a transverse,--Stephen Smith[23] and others, a longitudinal incision. The author had lately to secure the radial in its lower third, the superficialis volæ, and the radial again in the triangular space, in a case where division of the artery by a transverse cut had caused a large aneurism to form close above the annular ligament. TABLE illustrating anastomotic circulation after ligature of arteries of neck and upper limb. 1. Common carotid. (_a_) Across middle line: thyroids, linguals, facials, occipitals; also terminal branches of external carotids; also internal carotids by circle of Willis. (_b_) Of same side: occipital with vertebral; superior thyroid with inferior thyroid, etc. 2. Subclavian, 3d part.