Video: Blood vessels of the hand

Brrrr, it's so cold. Man, why didn't I bring my gloves? Is it just me or are my hands starting to look a bit funny? They're getting a bit sore and numb! What's happening? Guys? Anyone?

Looks like this might be a circulatory problem. It appears that the arteries of the hand are spasming, resulting in impeded arterial supply to the fingers. But why and how does this happen? And even more importantly, how do we fix it? Well, that's all to be uncovered as we explore the arteries and veins of the hand.

In today's tutorial, we'll begin with a brief overview of the anatomical structure of the hand. We'll then take a look at the main arteries and veins of the hand and explore their origins and areas supplied or drained by them. We'll finish off by taking a look at a clinical note relevant to the blood vessels of the hand to apply and consolidate our knowledge.

Before we dive right into the main topic of this tutorial, let's quickly get oriented with the hand itself.

As the most distal part of the upper limb, the hand begins at the wrist – a region that is also known as the carpus. The hand has a posterior surface, or dorsum, and an anterior surface, or palm. The hand is further subdivided into the metacarpal region or the metacarpus – a region that contains the metacarpal bones – and the digits or the fingers which contain the phalanges.

Alright, that's pretty straightforward. So what's so complex about the hand? Well, its complexity is reflected in its collective structure of bones, muscles, intersecting nerves, arteries, and veins. While this may resemble a handful of spaghetti right now, we're going to sort it all out as we venture through the arteries and veins of the hand. So let's dive right in and begin with taking a look at the arteries that supply the hand.

As with the rest of our body, the arterial supply system originates at the aorta which delivers oxygenated blood from the heart. Emerging off the aorta and into each upper limb is a continuous arterial pathway that gives off many branches which supply the entire extremity. The main artery of the arm – the brachial artery – divides or bifurcates at the cubital fossa into the ulnar and radial arteries. These two vessels descend in the forearm and give rise to all the arteries of the hand that perfuse its bones, muscles, and joints with oxygen-rich blood.

The radial artery originates as one of the terminal branches of the brachial artery and travels along the radial side of the forearm, just deep to the brachioradialis muscle. As it approaches the wrist, it travels posteriorly to run along the dorsal aspect of the carpus. Flipping the hand over, we can see that the radial artery passes along the floor of the anatomical snuffbox and extends through the first interosseous space to reach the palm of the hand where it meets and anastomosis with the ulnar artery to form the deep palmar arch, which we will meet later. Along its route, the radial artery gives off several branches which supply structures of the palmar and dorsal surfaces of the hand. We'll meet some of these branches along the way.

Another important branch providing arterial supply to the hand is the ulnar artery. Arising as the other terminal branch of the brachial artery, the ulnar artery descends along the ulnar aspect of the forearm. It passes superficial to the flexor retinaculum through Guyon's canal to enter the palm of the hand. The ulnar artery gives off several branches before anastomosing with the superficial branch of the radial artery to form the superficial palmar arch of the hand which we'll explore in detail in a moment.

The arteries of the hand can largely be divided into palmar and dorsal groups. The palmar arteries either contribute to the formation of or branch from the main arches of the palm of the hand which include the superficial and deep palmar arches of the hand. Arteries on the dorsal aspect of the hand contributes to the formation of the three major arches of the dorsum of the hand – the dorsal radiocarpal anastomosis, the dorsal carpal arch, and the basal metacarpal arch. Let's begin with the arteries of the palm of the hand.

As the radial artery descends through the forearm just proximal to the carpus, it gives off a small branch – the palmar carpal branch of the radial artery. This small artery courses along the wrist joint to anastomose with another small branch known as the palmar carpal branch of the ulnar artery. The palmar carpal branch of the ulnar artery similarly branches directly from the ulnar artery at the level of the distal ulna. The anastomosis between the palmar carpal branches is joined by the anterior interosseous artery and recurrent branches from the deep palmar arch thus forming the palmar carpal arch or palmar radiocarpal arch as it is also known as. This arterial network supplies the carpal articulations and bones of the anterior aspect of the wrist joint.

Just before the radial artery curves around the carpus, it gives off a small branch known as the superficial palmar branch of the radial artery. This small artery supplies the thenar muscles as it passes over them and terminates when it joins with the ulnar artery to form the palmar anastomosis known as the superficial palmar arch which we'll take a look at next. The superficial palmar arch gives off a number of branches which include the three common palmar digital arteries and palmar digital artery of the little finger. We will explore the blood supply of the superficial palmar arch as we look at each of its associated branches.

The common palmar digital arteries are responsible for directing blood to the proximal phalanges, metacarpophalangeal joints, and third and fourth lumbrical muscles. At the level of the metacarpophalangeal joints, each common palmar digital artery divides into proper palmar digital arteries which course along opposing sides of fingers 2 to 5. They give off small dorsal branches as they extend into the middle and distal phalanges. These vessels perfuse the corresponding distal interphalangeal joints, middle and distal phalanges, along with the surrounding soft tissue. If you're wondering why the thumb is being left out of all the fun, stay tuned! We'll explore its own blood supply later in this tutorial.

Before moving on to take a look at the deeper arteries of the palm of the hand, let's first explore the palmar arterial supply of the little finger. Unlike the other proper palmar digital arteries, the palmar digital artery of the little finger arises directly from the superficial palmar arch. It then courses medially traveling over the shaft of the fifth metacarpal to extend along the ulnar aspect of the fifth digit. This small artery contributes to the arterial supply of the little finger.

Alright, let's move on to take a look at some of the deeper arteries of the palm of the hand, starting with the deep palmar branch of the ulnar artery. This artery terminates as it anastomosis with the radial artery forming the deep palmar arch which we'll meet next. As the deep palmar arch crosses the base of the metacarpals and interossei, it gives off the palmar metacarpal arteries and the recurrent branches of the deep palmar arch. The deep arch and its branches have a prolific blood supply area which we'll take a look at now as we explore its branches.

As we've already seen earlier in this tutorial, arising from the deep palmar arch and ascending in a proximal direction are several recurrent branches. The recurrent branches ascend to the carpal bones and intercarpal articulations before terminating at the palmar carpal arch. Also arising from the deep palmar arch are the three palmar metacarpal arteries. These arteries course distally and run along the interossei of the second to fourth spaces.

At the digital clefts, each palmar metacarpal artery unites with a corresponding common palmar digital artery of the superficial palmar arch as they span and supply the associated lumbricals. Each palmar metacarpal artery gives off small perforating branches which cross the second to fourth interosseous spaces between the dorsal interossei muscles and anastomose with the dorsal metacarpal arteries. In doing so, these small arteries contribute in providing collateral blood supply to the dorsum of the hand.

Moving on to the arteries of the thumb, we meet the princeps pollicis artery. The princeps pollicis artery, otherwise known as the principal artery of the thumb, branches off the radial artery in the web space between the thumb and the index finger and splits into two vessels running along each side of the thumb. It provides the main blood supply to the thumb which is isolated from the other digits. The princeps pollicis artery bifurcates and gives off two branches – the palmar ulnar and radial digital arteries of the thumb.

The palmar radial digital artery courses along the radial aspect of the first digit to supply the palmar surface of the distal phalanx of the thumb. The palmar ulnar digital artery courses along the ulnar aspect of the distal phalanx supplying the structures of this area. These two arteries anastomose at the apex of the digit to form the pollicial arch.

Next, I'd like to quickly mention the radialis indicis artery. The origin of this vessel may vary from person to person. It has been reported to originate as a branch of the princeps pollicis artery but may even also arise from the superficial palmar arch or the first dorsal metacarpal artery. For the sake of this tutorial and to avoid confusion, we will identify the origin of the radialis indicis artery to arise directly from the princeps pollicis artery as this is the most frequently described across textbooks. It travels along the lateral aspect of the index finger supplying this part of the digit. It usually anastomosis with the superficial palmar arch at the transverse head of the adductor pollicis muscle.

Now we're going to turn the hand over and take a look at the arteries on the dorsal aspect of the hand.

Similar to the palmar surface, the dorsum of the hand is mainly supplied by the radial and ulnar arteries. There are three main arterial networks located on the dorsal aspect of the hand – the dorsal radiocarpal anastomosis, the dorsal carpal arch, and the basal metacarpal arch. Let's begin with taking a look at the dorsal radiocarpal anastomosis which is the most proximally located arterial network on the dorsum of the hand. As its name suggests, it is present at the level of the radiocarpal joint and it's formed by contributions from the radial, ulnar, and anterior interosseous arteries of the distal forearm. This network of vessels supplies soft tissue and bony structures of this region.

Just distal to the dorsal radiocarpal anastomosis is the dorsal carpal arch. The formation of the dorsal carpal arch may vary. Most commonly, it is formed by an anastomosis between the dorsal carpal branch of the radial artery and the anterior interosseous artery of the forearm. However, it may also be formed by an anastomosis between the dorsal carpal branch of the radial artery and the dorsal carpal branch of the ulnar artery along with contributions from both the posterior and anterior interosseous arteries of the forearm. This is the formation that we can see here in this image as this is traditionally the classic description. This dynamic network is situated at the level of the midcarpal joint.

Branching from this arterial arch are the second to fourth dorsal metacarpal arteries. The first dorsal metacarpal artery arises directly from the radial artery. The dorsal metacarpal arteries live up to their name, traversing along both shafts of the metacarpal bones. These arteries provide blood to the corresponding dorsal interossei muscles and associated digits. As dorsal metacarpal arteries 2 to 4 course distally, they bifurcate to form the dorsal digital arteries which run along opposing sides of digits 2 to 5. These arteries provide blood supply to the corresponding phalanges of the digits and proximal interphalangeal joints and terminate as they anastomose with the proper palmar digital arteries. The first dorsal metacarpal artery also bifurcates into two branches – a dorsal ulnar digital branch to the thumb and a communicating branch which extends to supply the ulnar aspect of the index finger. The dorsal radial digital branch of the thumb arises directly from the radial artery which we'll look at a little later.

Weaving in between the proximal portions of the dorsal metacarpal arteries is the basal metacarpal arch. This arch is present at the level of the carpometacarpal joints and is formed by contributions of the radial artery and the dorsal digital artery of the fifth finger. It links the dorsal metacarpal arteries together and functions to provide arterial blood to the carpometacarpal joints and base of the metacarpals. Arterial supply to the dorsal aspect of the fifth finger is supplied by the dorsal digital artery of the little finger. This artery arises from the dorsal carpal branch of the ulnar artery and extends along the ulnar aspect of the little finger.

Onto the final arteries of the hand – the dorsal digital arteries of the thumb.

The dorsal radial digital artery of the thumb usually arises directly from the radial artery; however, its origin point is highly variable. This small artery supplies the radial aspect of the thumb. The dorsal ulnar digital artery of the thumb arises from the bifurcation of the first dorsal metacarpal artery. It courses along the medial aspect of the thumb supplying the structures of this area. The other terminal branch of the first dorsal metacarpal artery is the communicating branch. This small branch extends to the lateral aspect of the index finger to supply structures of this area.

Now that we have explored the arteries of the hand, we're ready to move on to the veins of the hand.

Veins convey blood from the periphery back to the heart. The veins of the hand drain and conduct deoxygenated blood into the larger veins that ascend the upper limb including the radial, ulnar, basilic, and cephalic veins. Focusing on the hand, there are several venous networks and smaller veins responsible for the drainage of blood. Within the palm, we can see both the superficial palmar venous arch and the deep palmar venous arch which drain into the deep veins of the forearm. These venous networks are closely associated with the palmar arterial arches which we came across earlier in this tutorial and accomplish venous drainage via the palmar digital and palmar metacarpal veins. If we flip the hand around, we can also identify an extensive dorsal venous network on the dorsum of the hand made up of the dorsal metacarpal, dorsal digital, and intercapitular veins. We'll explore each of these venous networks beginning with the veins on the palmar surface of the hand.

Venous drainage of the palm of the hand begins with the palmar digital veins and the common digital veins. This group of veins are responsible for venous drainage of the palmar aspect of the fingers. This group of veins typically accompany the proper palmar digital arteries. Connecting the palmar and dorsal digital veins are small oblique intercapitular veins allowing for communication between the dorsal and palmar venous networks. The palmar digital veins drain to both the dorsal venous network via the oblique intercapitular veins and to the superficial venous arch.

Taking a look at this image, we can concentrate on the palmar metacarpal veins and visualize how they drain into the deep palmar venous arch. The palmar metacarpal veins are responsible for the venous drainage of the palm of the hand. This group of veins course proximally along the metacarpals and are formed distally by the coalition of the palmar digital veins.

Now let's explore the venous arches of the palm of the hand. As its name suggests, the superficial palmar venous arch is located on the palmar surface of the hand, deep to the palmar aponeurosis. This network receives venous blood flow from the palmar or common digital veins seen along the sides of the fingers. Deoxygenated blood collected within the superficial palmar arch mainly drains into the ulnar vein with minor drainage to the median antebrachial vein and to the dorsal venous network via oblique intercapitular veins. If you stretch your palm out wide, you might be able to catch a glimpse of the superficial palmar venous arch.

The deep palmar venous arch, which we can see highlighted in green, courses along the bases of metacarpals 2 to 5 and receives blood from the palmar metacarpal veins and the palmar digital vein of the thumb. This venous network predominantly drains into the radial veins of the forearm.

Flip the hand over because it's time to explore the venous drainage of the dorsum.

Let's begin by taking a look at the dorsal digital veins. Similar to their palmar counterparts, the dorsal digital veins run along either side of each finger and ultimately drain into the dorsal venous network of the hand via the dorsal metacarpal veins. The exception to this drainage pathway is the dorsal digital vein on the radial aspect of the index finger, the dorsal digital vein on the ulnar aspect of the little finger, and the dorsal digital veins of the thumb. These veins bypass the dorsal metacarpal veins and drain directly to the dorsal venous network. This group of veins function to drain the dorsal aspect of the fingers. As the dorsal digital veins ascend proximally, they unite to form three dorsal metacarpal veins.

As we have already seen, the dorsal metacarpal veins originate as a continuation of the dorsal digital veins. They course proximally along the dorsal aspect of the metacarpals and drain the dorsum of the hand before ultimately uniting to form the dorsal venous network.

Finally, we have reached the most robust drainage system of the hand – the dorsal venous network. This superficial meshwork of veins gives rise and drains into two important superficial veins of the upper limb – the basilic vein arising from the medial or ulnar aspect of the network and the cephalic vein emerging from the lateral or radial aspect. Within this pathway of venous drainage, blood being conducted through the lateral aspect of these vessels enters the cephalic vein whereas blood in the medial aspect drains through the basilic vein. The accessory cephalic vein also contributes to the venous drainage of the dorsal venous network as we can see here.

The dorsal venous network functions to drain the dorsal aspect as well as some palmar regions of the hand by its tributaries – the dorsal metacarpal veins, the intercapitular veins, the dorsal digital vein of the radial aspect of the index finger, the dorsal digital vein of the ulnar aspect of the little finger, and the dorsal digital veins of the thumb. The easy visibility of the dorsal venous network on the back or dorsum of the hand makes it an ideal site for medical procedures requiring venous access such as venipuncture.

Phew! That's a lot of arteries and veins to remember. Let's work on consolidating that knowledge by applying it to a clinical scenario.

Right – back to our freezing, cold friend. As we have seen, there are a lot of vessels within our hands, therefore, suggesting that they need plenty of oxygenated blood to function. But what happens if blood fails to reach our hands and fingers? Raynaud's phenomenon refers to a discoloration of the fingers that turn white or pale then blue, and finally, red accompanied by mild pain and numbness. In this condition, the blood vessels constrict in an exaggerated way or spasm decreasing the blood flow to parts of the body; typically, the fingers and toes. This happens in response to triggers such as cold, stress, or emotional upset. It can be classified as primary or secondary.

Primary Raynaud's phenomenon occurs on its own and is generally a benign condition. Secondary Raynaud's phenomenon is the term used when Raynaud's is associated with another medical condition, often an autoimmune or connective tissue disease. Treatment includes nonpharmacologic lifestyle measures such as avoiding exposure to cold and using warm gloves and socks and vasodilator drugs like calcium channel blockers.

Go ahead and give yourself a big round of applause because you've made it to the end of this tutorial. Now let's quickly summarize what we've learned before you take off.

To kick things off, we had a look at the arteries of the hand. While exploring each of these vessels, we discovered the origin of either the radial or ulnar arteries. We began with exploring the arteries of the palm of the hand starting with the palmar carpal branches of the radial and ulnar arteries which contributed to the formation of the palmar carpal arch. Moving distally, we identified the superficial palmar branch of the radial artery which, together with the ulnar artery, forms the superficial palmar arch. We learned how the superficial palmar arch gives rise to the palmar digital artery of the little finger and common palmar digital arteries which in turn bifurcates into the proper palmar digital arteries.

We dove a little deeper to identify the deep palmar branch of the ulnar artery. This arterial branch together with the radial artery forms the deep palmar arch. Branches of the deep palmar arch include the palmar metacarpal arteries and the recurrent branches of the deep palmar arch. Still on the palmar aspect of the hand, we identified the arterial supply of the thumb. The main artery of the thumb is the princeps pollicis artery. It bifurcates into the palmar radial and ulnar digital arteries of the thumb which together form the pollicial arch. Next, we came to the radialis indicis artery which stems from the princeps pollicis artery.

Transitioning to the dorsum, we explored the three arches of the dorsum of the hand beginning with the dorsal radiocarpal arterial anastomosis which is formed by contributions of the radial, ulnar, and anterior interosseous arteries of the distal forearm. Next, we explored the dorsal carpal arch. We learned how this network gives rise to dorsal metacarpal arteries 2 to 4, and finally, how these arteries terminate as the dorsal digital arteries. We identified the dorsal arterial supply to the little finger to be the dorsal digital artery of the little finger which arises from the dorsal carpal branch of the ulnar artery. Weaving in between the base of the dorsal metacarpal arteries is the basal metacarpal arch which is formed by contributions of the radial artery and the dorsal digital artery of the little finger.

Finally, we explored the dorsal arterial supply of the thumb. The first dorsal metacarpal artery arises directly from the radial artery and bifurcates to form the dorsal ulnar digital artery of the thumb and a communicating branch. The dorsal radial digital artery arises directly from the radial artery.

Our next topic was the veins of the hand and we explored where each vein receives blood from and drains into. We began our exploration of the venous drainage of the hand on the palmar aspect and explored the palmar digital veins which drained to the superficial venous arch and dorsal venous network via the intercapitular veins. Next, we met the palmar metacarpal veins and witnessed how they drained to the deep palmar venous arch of the hand. At this point, we explored the superficial and deep palmar venous arches. The superficial palmar venous arch receives blood from the palmar digital veins and drains to the ulnar vein. The deep palmar venous arch receives blood from the palmar metacarpal veins and the palmar digital vein of the thumb before draining into the radial vein.

We concluded our review of the veins with the dorsal venous network and its tributaries – the dorsal metacarpal, dorsal digital, and intercapitular veins of the hand. Here we learned how this robust network is responsible for the venous drainage of the dorsum of the hand. This superficial meshwork of veins gives rise and drains into two important superficial veins of the upper thumb – the basilic vein and the cephalic vein – emerging from the lateral aspect. To finish, we explored the presentation, cause, and treatment for Raynaud's phenomenon and why it's so important to keep your hands warm.

Hooray! We did it! Fantastic work, everyone! We hope you enjoyed this tutorial and can't wait to see you next time. Happy studying!