left subclavian artery, an artery, divided into three parts, that arises from the aortic arch to supply the vertebral column, spinal cord, ear, and brain. The short second part lies dorsal to the scalenus anterior and forms the arch described by the vessel. The third part runs from the scalenus anterior to the first rib, where it becomes the axillary artery. Compare right subclavian artery. See also subclavian artery.
