Subclavian Vein

What is the subclavian vein?

Your subclavian vein is a deep vein that moves oxygen-poor blood from your upper body back to your heart. You have one on each side of your body. Your right subclavian vein carries blood from your right upper body. Your left subclavian vein carries blood from your left upper body.

What is the function of the subclavian vein?

Your subclavian veins help circulate blood through your upper body. That includes your arms, head and neck. Your blood moves through a complex network of blood vessels including arteries, veins and capillaries. Your arteries carry oxygen-rich blood to your organs and tissues. Meanwhile, your veins collect oxygen-poor blood that contains waste products. Your veins carry this blood back to your heart so it can gain more oxygen in your lungs and begin a new journey around your body.

To make it back to your heart, your oxygen-poor blood has to travel through a series of veins. Like roads in a small town, your veins connect with each other and branch off in different directions. But they all lead back to the same place (your heart).

Like many other veins, your subclavian veins run parallel with arteries that have the same name. Picture two narrow one-way streets that run side-by-side. Each subclavian artery carries blood away from your heart. And alongside it, your subclavian vein carries blood toward your heart.

Besides helping your blood flow, your subclavian veins also play a role in certain medical procedures.

• Central venous access. Healthcare providers may use your subclavian vein for central venous access. This procedure is also known as a “central line.” Each year in the U.S., providers insert over 5 million central lines in people who need care, especially in the ICU. Catheters are small devices that give your body fluids or medications. Central venous access is an important part of medical care, but it can lead to complications. These include bleeding, infection, arrhythmia, venous thrombosis and pneumothorax (lung collapse).
• Pacemaker wires. Healthcare providers may use your subclavian vein to insert pacemaker wires. As with central lines, this must be done carefully to avoid complications.

Where are the subclavian veins located?

Your right and left subclavian veins both run just below your collarbone (clavicle). Each subclavian vein begins near the top of your ribcage, next to your shoulder. It forms an arch that curves back down toward your heart. Picture a letter “m” that spreads across your chest, with the dip in the middle touching the top of your heart. Your subclavian veins are the top peaks of the “m.”

Where do the subclavian veins receive blood from?

Your subclavian veins receive blood from the axillary veins, which collect blood from many smaller veins in your arms and hands. Your axillary veins are the outer edges of the letter “m”, leading up to your subclavian veins at the peaks. Your subclavian veins then drain into your right and left brachiocephalic veins. Those are the two curves in the middle of the “m”. At the middle dipping point, your brachiocephalic veins merge to form the superior vena cava. That’s the large vein that carries blood down into your heart.

Your left and right subclavian veins connect with other veins to carry oxygen-poor blood back to your heart.

What are subclavian veins made of?

Like your other veins, your subclavian veins are made of three layers of tissues and fibers:

• The tunica adventitia (outer layer) gives structure and shape to your vein.
• The tunica media (middle layer) contains smooth muscle cells that allow your vein to get wider or narrower as blood passes through.
• The tunica intima (inner layer) has a lining of smooth endothelial cells, allowing blood to move easily through your vein.

What conditions or disorders affect the subclavian vein?

Conditions that can affect your subclavian veins include:

• Deep vein thrombosis (DVT). If a blood clot blocks your subclavian vein, you can develop deep vein thrombosis. DVT usually occurs in people’s legs. But sometimes a clot can block a vein in your upper body, including your subclavian vein. This can happen as a complication from a central venous catheter. DVT is a dangerous situation that can lead to a pulmonary embolism. Symptoms of DVT include swelling, discomfort or heaviness in your arm.
• Axillary-subclavian vein thrombosis. This condition is also called Paget-Schroetter syndrome or “effort thrombosis.” It’s a rare form of DVT that affects about 3,000 to 6,000 people in the U.S. each year. Most people diagnosed with this condition are young (ages 15 to 45). They usually play sports or do heavy lifting at work. Often, repeated motions like lifting your arm over your head can trigger this problem. Symptoms include arm swelling, pain and discoloration (turning blue).

If you have symptoms of these conditions, call 911 right away. These are medical emergencies that need immediate care.

How can I keep my veins healthy?

There are several things you can do to keep your subclavian vein — and all your other veins — working at their best.

• Go for walks (aim for 30-minute walks, at least five days a week).
• Get up and move around throughout the day. This keeps your blood moving throughout your body.
• Eat a heart-healthy diet to lower your blood pressure, cholesterol and weight.
• Drink plenty of water.
• If you develop any symptoms of vein problems, even if they seem small, call your provider. Catching problems early can help avoid serious problems down the road.

A note from Cleveland Clinic

Your subclavian vein is an important part of your venous system. It helps move blood from your upper body back to your heart. If you have a history of vein issues like blood clots, talk with your healthcare provider. They’ll help you find ways to lower your risk of future problems.