The aorta originates from the left ventricle. It initially passes upward to the right as the ascending aorta until it reaches the level of the sternal angle where it forms an arch (Arch of the Aorta) over the bifurcation of the pulmonary trunk and the root of the left lung. The arch of the aorta lies in the sagittal plane directed posteriorly along the left side of the vertebral column at the level of the fourth thoracic vertebra. Thereafter, the aorta continues as the descending aorta to the level of the fourth lumbar vertebra. The branches of the arch of the aorta are the brachiocephalic trunk, the left common carotid and left subclavian.