The subclavian artery is a major blood vessel that carries oxygen-rich blood from the heart to the upper body, supplying the head, neck, and arms. There are two subclavian arteries, one on each side of the chest, located just below the collarbones. They distribute blood to various regions above the diaphragm.
Anatomical Location and Path
The subclavian arteries are situated beneath the collarbones on either side of the upper chest. The left subclavian artery emerges directly from the aortic arch, originating as one of its three primary branches. In contrast, the right subclavian artery originates as a branch of the brachiocephalic trunk, a short artery that also gives rise to the right common carotid artery. These distinct origins highlight a slight asymmetry in the upper body’s major vascular architecture, reflecting different developmental pathways.
From its origin, each subclavian artery extends laterally, passing behind the anterior scalene muscle in the lower neck. It then arches over the first rib before continuing into the armpit region, where it transitions into the axillary artery. This pathway allows the vessel to deliver blood efficiently to the shoulder, arm, and parts of the neck and head.
Vital Branches and Their Destinations
The subclavian artery gives rise to several important branches that distribute blood to various regions. The vertebral artery is one such branch, ascending through the transverse foramina of the cervical vertebrae before entering the skull. Inside the skull, it contributes significantly to the brain’s blood supply, particularly the posterior cerebrum and brainstem.
The internal thoracic artery descends into the chest cavity, running parallel to the sternum. This vessel provides blood to the anterior chest wall, including the intercostal muscles, and also supplies the breast tissue in females. Surgeons frequently utilize the internal thoracic artery in coronary artery bypass graft procedures due to its reliable blood flow and proximity to the heart.
The thyrocervical trunk and costocervical trunk are two other major branches arising from the subclavian artery. The thyrocervical trunk provides blood to structures in the neck, such as the thyroid gland, and muscles in the shoulder and upper back. The costocervical trunk supplies muscles in the neck and upper back, along with the first two intercostal spaces of the chest wall.
Common Conditions Affecting the Artery
Several medical conditions can impact the subclavian artery, affecting blood flow and overall health. Atherosclerosis involves the buildup of fatty plaques within the artery walls, narrowing the vessel and reducing blood flow. This hardening of the arteries can lead to arm pain during exertion or noticeable differences in blood pressure between the arms.
Thoracic outlet syndrome occurs when nerves or blood vessels, including the subclavian artery, become compressed in the confined space between the collarbone and the first rib. This compression can cause numbness, tingling, weakness, or pain in the arm and hand.
Takayasu’s arteritis is a rare inflammatory disease that primarily affects the aorta and its major branches, such as the subclavian arteries. This inflammation can lead to narrowing, blockage, or weakening of the artery walls, potentially causing reduced blood flow to the arms and head.
Subclavian steal syndrome is a condition where blood flow is reversed in the vertebral artery due to a significant narrowing or blockage in the subclavian artery, typically before the vertebral artery branches off. Blood is “stolen” from the brain’s circulation to supply the arm, especially during arm exercise, potentially leading to neurological symptoms like dizziness or fainting.