Video: Main arteries of the upper limb
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Rivers have been described as the arteries of our planet. They convey water, sediments, and solutes from the headwaters to the oceans. These natural flowing water courses are full of life and serve a source of important resources to sustain life on earth. Analogously, we can also think of arteries as the rivers of our body. They are responsible for delivering oxygen and nutrients to all cells and, like the rivers of the earth, arteries follow their own course and branch off to different pathways.
The extensive and intricate network of arteries in the human body is not always easy to follow especially in complex regions such as the upper limbs, but don't blame yourself if you feel like you're getting lost. Fear not! Today's tutorial can help and act as your map and compass. Come with me as we navigate through the main arteries of the upper limb.
So what exactly will we cover today? Let's find out in this overview.
The arteries of the upper limb supply oxygenated blood from the heart to the arm and forearm all the way to the fingertips. That is exactly the route we're going to follow during this tutorial. We'll start proximally by looking at the arteries of the shoulder, axilla, and scapular region. Here we'll talk about the subclavian and axillary arteries as well as the anastomotic network around the scapula. We'll then move on to the arteries of the arm – the brachial artery and its main branch, the deep brachial artery. Moving further down, we will describe the arteries of the forearm – the radial and ulnar arteries.
At the distal end of the upper limb, we will examine the arterial network supplying the wrist and the hand with the special emphasis on the superficial palmar arch, the deep palmar arch, and the dorsal carpal anastomosis. Finally, we'll finish up with some clinical notes. Let's begin at the proximal end with the arteries of the shoulder, axilla, and scapular region.
The artery supplying blood to the upper limb is the subclavian artery, an important artery located at the root of the neck inferior and deep to the clavicle. The subclavian artery continues throughout the entire upper limb changing name along the way based on the region it supplies. The right subclavian artery arises from the brachiocephalic trunk while the left subclavian artery arises directly from the aortic arch. When the subclavian artery passes the lateral border of the first rib and enters the region called the axilla, it becomes the axillary artery. Throughout its course, this artery is closely related to the brachial plexus. In this image, you can see the axillary artery traveling through the winding brachial plexus. It gives off numerous branches which mostly supply the musculature in lateral thoracic and scapular regions.
Speaking of the scapular region, we have an important network of vessels here known as the scapular anastomosis. An arterial anastomosis refers to a group of interconnecting arteries providing alternative route for blood supplying a particular region. The extreme mobility of the shoulder joint may result in kinking of the axillary artery and temporary occlusion of its lumen. To compensate, this important arterial anastomosis exists between branches of the subclavian and distal axillary arteries. The anastomosis provides an alternative route for blood to reach the upper limb if the axillary artery is blocked thus ensuring an adequate blood flow to the upper limb irrespective of the position of the arm.
Now that we have explored the main arteries of the shoulder, axillary, and scapular region, let's move on to the arteries of the arm.
At the inferior border of the teres major muscle, the axillary artery becomes the brachial artery. As its name implies, it is the main artery supplying the blood to the arm. It travels with the median nerve through the anterior compartment of the arm deep to the biceps brachii muscle. Proximally, it runs medial to the humerus before moving more anteriorly to lie between the epicondyles of the humerus anterior to the elbow joint. Here it lies immediately medial to the tendon of the biceps brachii muscle.
The main artery arising from the brachial artery is the deep brachial artery which we'll look at in greater detail shortly. The brachial artery also gives off branches to the muscles of the anterior compartment of the arm, the humerus, and the anastomotic network around the elbow. The brachial artery terminates by bifurcating at the cubital fossa giving rise to the radial and ulnar arteries which are the main suppliers of the forearm.
Before moving on to the forearm, let's take a closer look at the main branch of the brachial artery – the deep brachial artery – also known as the profunda brachii artery or deep artery of the arm. In this posterior view of the arm, we can see it more clearly. After arising from the brachial artery, it courses around the posterior surface of the humerus and accompanies the radial nerve within the radial groove. This artery is responsible for supplying the posterior compartment of the arm. The deep brachial artery also gives rise to branches that will take part in the anastomotic network around the elbow.
The blood supply around the elbow region is derived from a number of periarticular anastomoses that are formed by the collateral branches of the brachial and deep brachial arteries as well as the recurrent branches of the radial and ulnar arteries. This allows the blood to continue to flow distally even when the brachial artery is kinked and occluded during elbow flexion.
We're getting through it. Moving along distally, we're now on to the arteries of the forearm.
The radial artery is the smaller of the two terminal branches of the brachial artery. It begins in the cubital fossa, just distal to the elbow joint, and descends through the lateral or radial aspect of the anterior compartment of the forearm. In the middle third of its course, it runs medial to the superficial branch of the radial nerve. Throughout its course, the radial artery gives off muscular branches to its neighboring muscles.
Now it's time to look at the other side of the forearm to the larger of the two terminal branches of the brachial artery – the ulnar artery. Similar to the radial artery, the ulnar artery begins its course in the cubital fossa. It then descends along the medial or ulnar aspect of the anterior forearm before entering the palm of the hand alongside the ulnar nerve. Again, muscular branches arise from the artery along its course to supply the nearby muscles.
Just distal to the elbow joint, the ulnar artery gives origin to the interosseous arteries of the forearm. The anterior and posterior interosseous arteries pass distally on the anterior and posterior surfaces of the interosseous membrane, respectively. They give off nutrient arteries to the radius and the ulna, supply adjacent muscles in both the anterior and posterior compartments of the forearm, and finally, take part in the anastomosis around the wrist joint.
At this stage, what else is left for us to talk about except for the arteries of the wrist and hand.
The hand and wrist receive their arterial supply from an anastomotic network formed by the terminal branches of the radial and ulnar arteries. Because this is a rather complex network, let's break it down into two parts. First, we're going to look at the palmar aspect of the wrist and hand and then move to the dorsal view. We're going to start by looking at the palmar aspect of the wrist and hand. Here, the terminal branches of the ulnar and radial arteries give rise to two vascular arches – the superficial palmar arch and the deep palmar arch.
The superficial palmar arch is formed predominantly by the ulnar artery while the deep palmar arch is primarily formed by the terminal part of the radial artery. Both of these arches are located across the palm of the hand, but as their name implies, the superficial palmar arch is located closer to the surface in the palm. The superficial palmar arch also lies more distally compared to the deep palmar arch. To supply the digits, branches arise from both the superficial and deep palmar arches. Highlighted now are the common palmar digital arteries, arising from the superficial palmar arch.
Now you can see the branches of the deep palmar arch called the palmar metacarpal arteries. These small arteries join forces with the common palmar digital arteries to supply the digits beyond the metacarpophalangeal joints. After passing through these joints, the common palmar digital arteries each bifurcate to give rise to the proper palmar digital arteries which continue distally to the fingertips.
Now it's time to turn to the dorsal aspect of the wrist and hand. Here we find the dorsal carpal anastomosis, also known as the dorsal carpal arch. This anastomosis is formed by the joining of the dorsal carpal branches of the ulnar and radial arteries. It also receives contributions from the interosseous arteries. From this network arises the dorsal metacarpal arteries which are continuous with the dorsal digital arteries. Although the anastomosis allows mixing of blood supply to a degree, the radial artery mainly supplies the thumb and lateral side of the index finger. The remaining digits and the medial side of the index finger are mainly supplied by the ulnar artery.
And that's it for the anatomy of the main arteries of the upper limb. Before we finish up though, let's take a look at some clinical notes.
In this clinical section, we're going to focus on the brachial and radial arteries, which are the most commonly examined arteries in daily clinical practice. The brachial artery is suitable for assessing various clinical parameters, the most common of which is measuring blood pressure. The blood pressure cuff inflates around the arm to compress the brachial artery against the humerus, stopping blood flow. As the cuff deflates, it detects the pressure at which the blood starts flowing again to get systolic blood pressure. This is the pressure in the arteries just after the ventricles contract and eject blood into the circulation. The blood pressure monitor also gives the diastolic blood pressure which indicates how much pressure the blood is exerting against the artery wall while the ventricles of the heart are resting and refilling. It's sometimes useful to palpate the brachial artery to assess aspects of the pulse such as character and volume.
Now looking at the radial artery. It is most commonly used to assess pulse. In the distal forearm, the radial artery lies immediately lateral to the large tendon of the flexor carpi radialis muscle and directly anterior to the pronator quadratus muscle. Here, it is only covered by skin and fascia so the radial pulse can be felt by gently palpating the radial artery against the underlying muscle and bone. This is a common way to assess heart rate and rhythm. This is also an ideal vessel to collect arterial blood from to perform an arterial blood gas analysis – a test that measures the amount of oxygen and carbon dioxide in the blood as well as the blood pH.
And we're just about done. Let's take a quick look at a summary of what we learned today.
We started by looking at the arteries supplying the shoulder, axillary, and scapular regions – the subclavian and axillary arteries. We also explored the anastomotic network around the scapula. We then moved to the arm where we identified the brachial artery and its main branch, the deep brachial artery. We then saw the arteries of the forearm namely the radial artery and the ulnar artery. Finally, we studied the arterial network supplying the wrist and the hand highlighting the superficial palmar arch, the deep palmar arch, common palmar digital arteries, palmar metacarpal arteries, proper palmar digital arteries, the dorsal carpal anastomosis, dorsal metacarpal arteries, and the dorsal digital arteries. In our clinical notes, we looked at the significance of measuring blood pressure at the level of the brachial artery and of taking a patient's pulse using the radial artery.
That's it folks. We hope you enjoyed this tutorial. See you next time and happy studying!