This is known as our left subclavian artery. Now if we follow the left subclavian artery, it extends all the way to the left shoulder, the left arm and the left hand. So the left subclavian artery brings oxygen to these parts of our body. Now at this particular intersection point, we see that the left subclavian artery actually branches. So it branches and informs this artery, known as the left vertebral artery, that goes to our head portion of the body. It also extends many times, it permeates many times within our shoulder and arm portion as shown.