Ulnar Artery

The larger of the two terminal branches of the brachial artery arises in the antecubital fossa, and terminates in the palm of the hand by forming the palmar arches.

It lies successively on brachialis anticus, flexor profundus digitorum, pronator quadratus, anterior annular ligament.

It is covered by the (pronator radii teres, flexor sublimis digitorum, flexor carpi radialis, palmaris longus, flexor carpi ulnaris) superficial group of flexor muscles from internal condyle of humerus, and in its lower third is subcutaneous.

The median nerve crosses it above, being separated from the artery by the deep head of pronator radii teres, and on its inner side lies the ulnar nerve.

Branches

1. Common Interosseous, a very short trunk arising in the antecubital fossa, and dividing into the anterior and posterior interosseous arteries.

(a) The Anterior Interosseous artery runs down on the anterior surface of the interosseous membrane to the upper border of pronator quadratus, where it pierces the membrane and terminates in the posterior carpal arch.

(b) The Posterior Interosseous artery passes down the back of the forearm between the superficial and deep muscles which it supplies, and ends by anastomosing with the anterior interosseous artery and the posterior carpal arch.

2. Anterior Carpal, a small branch given off just above the wrist, which anastomoses with a similar branch from the radial artery to form the anterior carpal arch.

3. Posterior Carpal, a small branch which passes backwards and anastomoses with a similar branch from the radial artery to form the posterior carpal arch.

The ulnar artery crosses over the annular ligament, and terminates in the palm of the hand by dividing into superficial and deep branches.

The Superficial Palmar Arch is formed at the level of the distal border of the abducted thumb by the anastomosis of the superficial volar branch of the radial artery with the superficial terminal branch of the ulnar artery.

It lies on flexor brevis minimi digiti, opponens minimi digiti, and tendons of flexor sublimis digitorum. It is covered by palmar fascia and integument.

The Deep Palmar Arch is formed about three-quarters of an inch above the level of the superficial arch, by the anastomosis of the radial artery with the deep terminal branch of the ulnar artery.

It lies deeply in the palm on the bases of the metacarpal bones and the interossei muscles, and is covered by the flexor tendons. From the arches branches are given off for the supply of the muscles and fingers.

The back of the hand and fingers are supplied by branches given off from the radial artery while it lies on the back of the trapezium.

Veins of the Upper Limb.

The veins of the upper limb are arranged in two sets-superficial and deep. Both sets open eventually into a common trunk, known as the axillary vein, which continues as the subclavian vein to the innominate vein.

The Deep veins consist of venae comites arranged in the usual way, which open into the axillary vein.

The Axillary vein commences as the continuation of the basilic vein opposite the lower border of teres major, and terminates at the lower border of the first rib by becoming the subclavian vein. Its muscular relations are similar to those of the axillary artery, from which it is separated in the lower part of its course by the ulnar nerve, and above by the inner cord of the brachial plexus. To the inner side of the axillary vein lie the groups of axillary glands.

Tributaries

1. Venae Comites of the brachial artery at the lower border of the subscapularis muscle.

2. Cephalic vein at the upper border of pectoralis minor.

3. Tributaries corresponding to the branches of the axillary-artery.

The Superficial veins commence in the superficial fascia of the palm and dorsum of the hand, and of the fingers.

The superficial veins of the palm and palmar surface of the fingers are relatively small, and after forming a small irregular -plexus end in the median and anterior ulnar veins of the forearm.

On the dorsal aspect of the fingers are the dorso-lateral veins, which ascend along the dorso-lateral borders of each digit. They receive tributaries from all the tissues of the fingers, and terminate in a dorsal venous plexus, or arch, which lies at the level of the bases of the four inner metacarpal bones. The arch finally terminates in the radial and posterior ulnar veins of the forearm.