The surgical anatomy of the subclavian artery is routinely described in 3 distinct sections. The first or most proximal part of the artery extends to the medial border of the anterior scalene muscle. This portion of the artery gives rise to the internal mammary artery, vertebral artery, and thyrocervical trunk and is affected by thoracic outlet compressive syndromes only secondarily by retrograde propagation of thrombus. The second portion of the subclavian artery is retroscalene. This is often the site of stricture and positional compression and, when present, the proximal area of dilation or aneurysm formation. Finally, the third part of the subclavian artery extends from the lateral border of the anterior scalene to the lateral border of the first thoracic rib.1