The subclavian artery is a large artery on each side of the body that supplies blood to the arm, and through its vertebral artery branch, contributes blood flow to the brain. The right subclavian artery branches from the brachiocephalic trunk, while the left subclavian artery arises directly from the aortic arch. On ultrasound, the subclavian arteries can be evaluated in the supraclavicular region for stenosis or occlusion. Subclavian steal syndrome occurs when a severe stenosis of the subclavian artery proximal to the vertebral artery origin causes blood to flow backward down the vertebral artery to supply the arm, potentially causing symptoms of vertebrobasilar insufficiency (dizziness, visual changes). Doppler ultrasound of the vertebral artery showing reversed flow is a key diagnostic finding.
Sonography Term