The brachiocephalic trunk (also brachiocephalic artery or innominate artery, Latin: truncus brachiocephalicus) is the first and largest branch of the aortic arch that supplies the head, neck and the right arm. Soon after arising from the aorta, the brachiocephalic trunk divides into the right common carotid and right subclavian arteries.
There is no brachiocephalic trunk for the left side of the human body, as the left common carotid and left subclavian arteries both arise directly from the aortic arch. However, there are two brachiocephalic veins.
The brachiocephalic trunk located in the mediastinum. It arises from the aortic arch at the level of the second right costal cartilage. Then it runs upward, backward, and to the right, and crosses the trachea. It then reaches the level of the upper border of the right sternoclavicular joint, where it divides into its terminal branches - the right common carotid artery and the right subclavian artery.
Usually, the brachiocephalic trunk has only terminal branches and has no side branches. However, sometimes it may give rise to the thyroidea ima - a small artery that supplies the lower part of the thyroid gland. The brachiocephalic trunk sometimes may give off a thymic or a bronchial branch.