The aortic arch is the main conduit through which arterial blood pumped from the left ventricle of the heart is transmitted to the entire body. Blood passes through the aortic valve and enters the ascending thoracic aorta. This is a tubular structure, 4 to 5 cm in length, and usually of uniform caliber. The ascending aorta is continuous with the aortic arch at about the right second costal cartilage. Blood is then directed into the upper extremities and the head and neck through the innominate artery, the left common carotid artery, and the left subclavian artery. These vessels are collectively referred to as the great vessels. They arise in that order (in most instances) from the aortic arch. The aortic arch is semicircle in shape. Beyond the takeoff of the great vessels, the diameter of the aortic arch is approximately two-thirds that of the ascending aorta.

In a typical situation, the first branch of the aortic arch is the innominate artery. This vascular pedicle ascends toward the right and divides into the right common carotid artery and the right subclavian artery.

The innominate artery continues beyond the takeoff of the right common carotid artery as the right subclavian artery. Arising from the superior aspect of the right subclavian artery (in order) are the right vertebral artery, the right thyrocervical trunk, and the right costocervical trunk. The right internal mammary artery arises from the inferior aspect of the right subclavian artery usually opposite that of the right vertebral artery.