Subclavian Artery

The subclavian artery is a major blood vessel located in your upper chest, beneath your collarbone (clavicle). You have two subclavian arteries, one on each side of your body. These arteries are crucial for supplying oxygen-rich blood to your arms, head, neck, and parts of your chest, ensuring these areas receive the vital nutrients they need to function properly.

What is the Subclavian Artery?

The subclavian artery is a large blood vessel that runs under your collarbone (clavicle) on both the left and right sides of your body. It is a vital part of your circulatory system, acting like a main highway for blood flow. These arteries branch off from the aorta, the body's largest artery, or from a major vessel connected to it, to deliver blood to your upper extremities and head.

Each subclavian artery begins near the top of your chest. The left subclavian artery branches directly from the aortic arch, which is the curved part of your aorta. The right subclavian artery typically branches from the brachiocephalic artery, a short vessel that first comes off the aortic arch and then divides into the right subclavian and right common carotid arteries. As the subclavian artery travels, it passes between your collarbone and your first rib. This pathway is important because it can sometimes be a site of compression. Before it reaches your armpit, it gives off several smaller branches that supply blood to your neck, chest wall, and spinal cord. Once it passes the outer border of your first rib, the subclavian artery changes its name to the axillary artery, which then continues down into your arm.

Function

The primary function of the subclavian artery is to deliver oxygen-rich blood to your upper limbs, including your arms and hands, as well as significant portions of your head and neck. Think of it as a critical pipeline ensuring that these areas receive a continuous supply of oxygen and nutrients, which are essential for muscle function, nerve activity, and overall tissue health.

Beyond supplying your arms, the subclavian artery has important branches that contribute to the blood supply of other vital areas. One key branch is the vertebral artery, which travels up through your neck to supply blood to your brain and spinal cord. This connection highlights the subclavian artery's role in maintaining neurological function. Other branches include the internal thoracic artery, which supplies the chest wall and breasts, and the thyrocervical trunk, which further branches to supply muscles in the neck, shoulder, and thyroid gland. This extensive network of branches ensures that a broad range of tissues and organs in the upper body receive the necessary blood flow to perform their functions effectively. Without proper blood flow through the subclavian arteries, these areas can experience weakness, pain, or other serious complications.

Related conditions

Several medical conditions can affect the subclavian artery, often impacting blood flow to the arms, head, or neck. These conditions can range from narrowing of the artery to abnormal bulges in its wall. Understanding these conditions is important for recognizing potential symptoms and seeking appropriate medical attention from a qualified clinician.

One common condition is **subclavian steal syndrome**. This occurs when there is a significant narrowing (stenosis) or blockage (occlusion) in the subclavian artery, usually before the vertebral artery branches off. Because of the blockage, blood flow to the arm is reduced. To compensate, blood may be "stolen" from the vertebral artery, which normally supplies the brain, to provide blood to the arm. This can lead to symptoms such as dizziness, vision changes, and arm pain or weakness, especially during exercise. Another condition is **thoracic outlet syndrome (TOS)**, which involves the compression of nerves or blood vessels, including the subclavian artery, in the space between your collarbone and your first rib. This compression can cause pain, numbness, tingling, and weakness in your arm and hand. TOS can be caused by anatomical abnormalities, injury, or repetitive movements. **Aneurysms** can also affect the subclavian artery. An aneurysm is a bulge or ballooning in the wall of an artery, caused by a weakening of the vessel wall. If a subclavian artery aneurysm grows large, it can press on nearby structures or, in rare cases, rupture, leading to serious bleeding. **Atherosclerosis**, the buildup of plaque in the arteries, is a common underlying cause of narrowing and blockages in the subclavian artery, contributing to conditions like subclavian steal syndrome.

Related tests

If your clinician suspects a problem with your subclavian artery, they may recommend specific tests to evaluate blood flow and identify any abnormalities. These diagnostic tools help to visualize the artery and its branches, allowing for an accurate diagnosis without requiring invasive procedures in most cases. The choice of test depends on your symptoms and the suspected condition.

A common initial test is a **duplex ultrasound**. This non-invasive test uses sound waves to create images of your blood vessels and measure blood flow. It can detect narrowing, blockages, or abnormal blood flow patterns in the subclavian artery, providing real-time information about its condition. For more detailed imaging, your clinician might order a **computed tomography (CT) angiography** or a **magnetic resonance (MR) angiography**. Both tests use advanced imaging techniques to create detailed pictures of your blood vessels. CT angiography uses X-rays and a contrast dye injected into your bloodstream, while MR angiography uses magnetic fields and radio waves, sometimes also with a contrast dye. These tests can clearly show the anatomy of the subclavian artery, identify blockages, aneurysms, or compression. In some cases, a more invasive procedure called **catheter angiography** may be performed. This involves inserting a thin, flexible tube (catheter) into a blood vessel, usually in your groin or arm, and guiding it to the subclavian artery. A contrast dye is then injected, and X-ray images are taken. This test provides very detailed images and can sometimes be combined with a procedure to treat the blockage, such as angioplasty, though treatment is outside the scope of this content.

Frequently asked questions

What are the common symptoms of a problem with the subclavian artery?

Problems with the subclavian artery can cause various symptoms, often related to reduced blood flow. You might experience pain, weakness, or numbness in your arm or hand, especially during activity. If blood flow to the brain is affected, symptoms can include dizziness, lightheadedness, vision changes, or difficulty speaking. These symptoms warrant a discussion with your clinician.

Can a blocked subclavian artery be dangerous?

Yes, a blocked subclavian artery can be dangerous. It can lead to reduced blood flow to your arm, causing pain and weakness. More seriously, if the blockage causes blood to be diverted from the brain (subclavian steal syndrome), it can lead to neurological symptoms like dizziness or fainting. In rare cases, severe blockages or aneurysms can have serious consequences, so medical evaluation is important.

How is the subclavian artery different from other arteries?

The subclavian artery is unique due to its specific location beneath the collarbone and its critical role in supplying blood to both the upper limbs and, via its vertebral branch, to the brain. While all arteries carry oxygenated blood away from the heart, the subclavian artery's anatomical position makes it susceptible to conditions like thoracic outlet syndrome and subclavian steal syndrome, which are less common in other major arteries.

What is subclavian steal syndrome?

Subclavian steal syndrome occurs when there's a significant narrowing or blockage in the subclavian artery before the vertebral artery branches off. This causes blood to be 'stolen' or reversed from the vertebral artery, which normally supplies the brain, to compensate for the lack of blood flow to the arm. This can lead to symptoms like arm pain, weakness, and neurological issues such as dizziness.

What causes the subclavian artery to become narrowed or blocked?

The most common cause of narrowing or blockage in the subclavian artery is atherosclerosis, a condition where fatty plaques build up inside the artery walls. Other causes can include blood clots, inflammation of the artery (arteritis), or external compression from surrounding structures, as seen in thoracic outlet syndrome. Injury or trauma can also lead to blockages.

Can lifestyle changes help prevent subclavian artery problems?

Maintaining a healthy lifestyle can significantly reduce your risk of developing conditions like atherosclerosis, which is a primary cause of subclavian artery problems. This includes eating a balanced diet, getting regular physical activity, maintaining a healthy weight, managing blood pressure and cholesterol, and avoiding smoking. These habits promote overall cardiovascular health and can help keep your arteries clear.

Sources

• MedlinePlus — Subclavian Artery
• Mayo Clinic — Subclavian Artery
• Cochrane Library — Subclavian Artery