Whenever circumstances may call for placing a ligature on the ulnar artery, as it lies between the superficial and deep flexor muscles, in the region of I L M, Plate 16, the course of the vessel may be indicated by a line drawn from a central point of the forearm, an inch or so below the level of the inner condyle--viz., the point F, and carried to the pisiform bone, T. The line of incision will divide obliquely the superficial flexors; and, on a full exposure of the vessel in this situation, the median nerve will be seen to cross the artery at an acute angle, in order to gain the mid-place in the wrist at Q. The ulnar nerve, d, Plate 16, passing behind the inner condyle, e, does not come into connexion with the ulnar artery until both arrive at the place O. It will, however, be considered an awkward proceeding to subject to transverse section so large a mass of muscles as the superficial flexors of the forearm, when the vessel may be more readily reached elsewhere, and perhaps with equal advantage as to the locality of the ligature. When either the radial or ulnar arteries happen to be completely divided in a wound, both ends of the vessel will bleed alike, in consequence of the free anastomosis of both arteries in the hand. DESCRIPTION OF PLATES 15 & 16. PLATE 15. A. Fascia covering the biceps muscle. B. Basilic vein, with the internal cutaneous nerve. C. Brachial artery, with the venae comites. D. Cephalic vein, with the external cutaneous nerve; d, the median nerve. E. A communicating vein, joining the venae comites. F. Median basilic vein. G. Lymphatic gland. H. Radial artery at its middle. I. Radial artery of the pulse. K. Ulnar artery, with ulnar nerve. L. Palmaris brevis muscle. [Illustration: Right arm, showing blood vessels, muscles and other internal organs.] Plate 15 PLATE 16. A. Biceps muscle. B. Basilic vein, cut. C. Brachial artery. D. Median nerve; d, the ulnar nerve. E. Brachialis anticus muscle; e, the internal condyle. F. Origin of radial artery. G. Supinator radii longus muscle. H. Aponeurosis of the tendon of the biceps muscle. I. Pronator teres muscle. K. Flexor carpi ulnaris muscle. L. Flexor carpi radialis muscle. M. Palmaris longus muscle. N. Radial artery, at its middle, with the radial nerve on its outer side. O. Flexor digitorum sublimis. P. Flexor pollicis longus. Q. Median nerve. R. Lower end of radial artery. S. Lower end of ulnar artery, in company with the ulnar nerve. T. Pisiform bone. U. Extensor metacarpi pollicis. [Illustration: Right arm, showing blood vessels, muscles and other internal organs.] Plate 16 COMMENTARY ON PLATES 17, 18, & 19. THE SURGICAL DISSECTION OF THE WRIST AND HAND.