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Subclavian artery

What Is It, Location, Branches, and More

Author:Anna Hernández, MD

Editors:Alyssa Haag,Ian Mannarino, MD, MBA

Illustrator:Jillian Dunbar

Copyeditor:Sadia Zaman, MBBS, BSc


What is the subclavian artery?

The subclavian artery is a paired blood vessel that provides blood supply to the upper limbs, as well as parts of the neck and brain. Both subclavian arteries are located on the root of the neck, a region that acts as a channel for neurovascular structures originating from the thorax to the head or upper limbs, and vice versa. From their origin, the subclavian arteries are surrounded by numerous structures that travel alongside them, including the external and anterior jugular veins, the subclavian veins, and nerves, such as the vagus nerve, phrenic nerves, and the sympathetic trunks.

Where is the subclavian artery located?

The subclavian arteries are located on the root of the neck, just beneath the clavicles (i.e. collarbones). The left subclavian artery arises directly from the aortic arch, about 1 cm distal to the origin of the left common carotid artery; the right subclavian artery in contrast arises from the brachiocephalic trunk, which is also where the right common carotid artery originates. Although the two subclavian arteries have different origins, they follow the same course within the neck. From their origin, they travel upwards and laterally towards the axilla, passing between the anterior and middle scalene muscles. Then, they begin to descend until they cross the lateral border of the first rib, where they become known as the axillary arteries.

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What is the function of the subclavian artery?

The main function of the subclavian artery is to provide blood supply to the upper limbs, as well as part of the head and neck through its several branches.

Each subclavian artery is divided into three parts based on its position relative to the anterior scalene muscle. The first part, known as the prescalene part, extends from the origin of the subclavian artery to the medial border of the anterior scalene muscle. This part gives off several branches, including the vertebral artery, which supplies part of the medulla, cerebellum, and brain; the internal thoracic artery, which supplies the anterior thoracic wall and breast tissue; and the thyrocervical trunk, which supplies blood to the larynx, trachea, esophagus, thyroid and parathyroid glands, as well as many other structures of the neck. The second part of the subclavian artery lies just behind the anterior scalene muscle and it gives off the costocervical trunk, which supplies the upper thorax and posterior deep cervical muscles. Finally, the third part, known as the postscalene segment, extends from the lateral border of the anterior scalene muscle to the lateral border of the first rib. This part gives off the dorsal scapular artery, which travels to the back to supply some muscles of the upper back and shoulder, such as the levator scapulae, trapezius muscles, and rhomboids. 

What happens if the subclavian artery is blocked?

When there’s a blockage or narrowing in the subclavian artery, blood flow towards the brain may be drawn away, or stolen, from the vertebrobasilar circulation into the subclavian artery. This is known as subclavian steal syndrome and occurs when blood flows retrograde from the vertebral or internal thoracic artery, as a result of a proximal narrowing or blockage of the subclavian artery. This syndrome typically affects the left side of the body due to the anatomical location of the left subclavian artery. The signs and symptoms of subclavian steal syndrome are usually transient and are more likely to appear when moving the arm vigorously, or when turning the head in the direction of the affected side. Clinical manifestations include symptoms caused by the reduced blood supply to the brain, such as dizziness, blurry vision, syncope, or neurological defects; in the arm, decreased blood flow may result in numbness in the arm and fingertip regions, reduced blood pressure on the affected side, as well as a differential pulse and blood pressure between the arms. Treatment of subclavian steal syndrome involves removing the obstruction from the subclavian artery to restore the blood flow.

What are the most important facts to know about the subclavian artery?

The subclavian artery is a large artery that supplies blood to the upper limbs, as well as parts of the head and neck. During its course, the subclavian artery is divided into three parts which are described relative to the anterior scalene muscle. The main branches of the subclavian artery include the vertebral artery, the internal thoracic artery, the thyrocervical trunk, the costocervical trunk, and the dorsal scapular artery. Once the subclavian artery reaches the axilla, it becomes known as the axillary artery

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Related links

Deep structures of the neck: Root of the neck
Vessels and nerves of the thoracic wall
Anatomy of the axilla

Resources for research and reference

Drake, R., Vogl, A. W., & Mitchell, A. (2019). Gray’s anatomy for students: With student consult online access (4th ed.). Elsevier - Health Sciences Division.

Hansen, J. T., Netter, F. H. 1., & Machado, C. A. G. (2019). Netter's clinical anatomy (4th ed.). Philadelphia, PA: Elsevier.

Shankar, K. N., & Nagalli, S. (2021). Subclavian Steal Syndrome. (2021, Jul 5). In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing LLC. Retrieved November 21, 2021 from: https://www.ncbi.nlm.nih.gov/books/NBK554599/