Branches

As soon as the ulnar artery passes the pisiform bone it gives off its deep branch which passes down between the abductor and flexor brevis minimi digiti to join the termination of the radial and form the deep palmar arch. From the convexity of the superficial arch four palmar digital arteries are given off. One goes to the ulnar side of the little finger while the other three go down between the metacarpal bones to the webs of the fingers. Here they may receive a small communicating branch derived from the deep palmar arch, and about 1 cm. (2/5 in.) back from the web divide into collateral digital branches which run along the palmar sides of the fingers. The digital nerves as they accompany the digital arteries are superficial to them.

Fig. 372.   Superficial palmar arch.

Fig. 372. - Superficial palmar arch.

The Radial Artery And Deep Palmar Arch

The radial artery reaches the wrist between the brachioradialis and flexor carpi radialis tendons. It then turns sharply toward the dorsum around the extremity of the styloid process of the radius. It crosses the external lateral ligaments and the scaphoid and trapezium bones to enter the palm between the bases of the metacarpal bones of the thumb and index finger. It then passes across the palm to the fifth metacarpal bone, where it receives the deep branch of the ulnar, which completes the formation of the deep arch. It lies beneath the flexor tendons and on the interossei muscles and bases of the metacarpal bones (Fig. 373).

Branches

The radial artery at the wrist gives off a posterior carpal branch which anastomoses with the posterior carpal branch of the ulnar to form a posterior carpal arch. From this arch descend three posterior interosseous arteries. The dorsal interosseous artery lying to the radial side of the index finger is called the dorsalis indicis. It comes off separately from the radial, and may be a branch from the radialis indicis.

As the radial artery enters the palm it gives off a large branch to the thumb called the princeps pollicis, and one to the palmar side of the index called the radialis indicis. Farther on, three palmar interosseous branches are given off which communicate at the webs of the fingers with the palmar digital arteries from the superficial arch. The deep palmar arch also sends a few recurrent branches up on the anterior surface of the carpus and three perforating branches between the metacarpal bones to the back of the hand.