the sinoatrial node receives its blood supply from the sinoatrial nodal artery. this blood supply, however, can differ hugely between individuals. for example, in most humans, this is a single artery, although in some cases there have been either 2 or 3 sinoatrial node arteries supplying the sa node. also, the sa node artery mainly originates as a branch of the right coronary artery; however in some individuals it has arisen from the circumflex artery, which is a branch of the left coronary artery. finally, the sa node artery commonly passes behind the superior vena cava, before reaching the sa node; however in some instances it passes in front. despite these many differences, there doesn’t appear to be any advantage to how many sinoatrial nodal arteries an individual has, or where they originate