In human anatomy, the subclavian arteries are two major arteries of the upper thorax (chest), below the clavicle (collar bone). They receive blood from the top (arch) of the aorta. The left subclavian artery supplies blood to the left arm and the right subclavian artery supplies blood to the right arm, with some branches supplying the head and thorax. On the left side of the body, the subclavian comes directly off the arch of aorta. On the right side of the body, the subclavian arises from the relatively short brachiocephalic artery (trunk) when it bifurcates into the subclavian and the right common carotid artery. The usual branches of the subclavian on both sides of the body are the vertebral artery, the internal thoracic artery, the thyrocervical trunk, the costocervical trunk and the dorsal scapular artery. The subclavian becomes the axillary artery at the lateral border of the first rib.