Aortic arch, great vessels, and important branches

This MR angiogram shows the aortic arch and great vessels as well as important branches, including the subclavian arteries, command and internal carotid arteries, and the vertebrobasilar system. (1) innominate (brachiocephalic) artery, (2) right subclavian artery, (3) right common carotid artery, (4) right vertebral artery, (5) basilar artery, (6) left vertebral artery, (7) left common carotid artery, and (8) left subclavian artery. The origin of the left vertebral artery from the left subclavian artery is not visible. The vertebral loop from one subclavian artery up the corresponding vertebral artery to the confluence of the vertebral arteries (where the basilar artery is formed) and down the opposite vertebral artery to the opposite subclavian artery is an important collateral pathway in patients with steno-occlusive disease of the innominate or subclavian arteries. (Contributed and edited by Dr. Douglas Lanska. Source: Ofir Glazer. Courtesy of Wikimedia Commons. Creative Commons Attribution-Share Alike 3.0 Unported license.)