(4.11)

Next, let’s look at the two main arteries of the hand, the radial, and the ulnar. In the dissection we’ll see, the arteries have been injected with red latex to make them more visible.

The radial artery runs down the forearm deep to brachioradialis. It lies on pronator teres, flexor digitorum superficialis, and flexor pollicis longus. In the distal foream the radial artery emerges from beneath brachioradialis, and lies superficially, between the border of the radius, which is here, and the tendon of flexor carpi radialis.

At the wrist, the radial artery gives off this superficial branch, then spirals around the lateral aspect of the wrist, running beneath the tendons of abductor pollicis longus, extensor pollicis brevis, and extensor pollicis longus. It passes between the two heads of the first dorsal interosseous muscle, one of which we’ll remove, and gives off branches to the thumb and sometimes the index. Finally it passes between the two heads of adductor pollicis, to enter the palm. We’ll see where the radial artery goes in a minute.

Now, let’s go back up to the elbow, and look at the ulnar artery. It has a much deeper course. The ulnar artery passes beneath pronator teres. To see where it goes, we’ll remove pronator teres, and flexor carpi radialis.

After passing beneath pronator teres, the ulnar artery gives off the common interosseous artery. It then passes between the two heads of flexor digitorum superficialis. To follow it we’ll go round to the ulnar side of flexor digitorum superficialis and raise it up. Here’s the ulnar artery. It runs down the forearm between flexor digitorum superficialis, and profundus.

In the distal forearm it emerges, along with the ulnar nerve, between flexor digitorum superficialis and flexor carpi ulnaris. At the wrist it passes through the tunnel in the side of the flexor retinaculum, to reach the hand.

Let’s just get re-oriented. Here’s the radial artery, with its superficial branch; here’s the ulnar artery. Emerging from its fibrous tunnel, the ulnar artery divides, into a large superficial branch, and a smaller deep branch. The deep branch dives between the hypothenar muscles.

The superficial branch runs behind the palmar aponeurosis, which we’ll remove, and runs across the palm in front of the flexor tendons. It usually ends by anastomosing with the superficial branch of the radial artery, forming a loop called the superficial palmar arch. The superficial palmar arch gives off these common digital arteries.

Each common digital artery divides into two digital arteries. Each digital artery runs along one side of the finger, beside the flexor sheath, in company with the digital nerve. At the tip of the finger the two digital arteries re-join, to form this terminal anastomosis.

Now let’s go back to the radial artery. We last saw the radial artery running around the wrist, and disappearing here between the heads of adductor pollicis. To see where it comes out, we’ll go round to the front of the hand and remove the superficial palmar arch, and the flexor tendons.

Here’s the radial artery emerging. It crosses in front of the interossei, usually anastomosing with branches of the ulnar artery to form the deep palmar arch.