artery to the sinuatrial (S-A) node

ascending atrial branch, usually (55%) arising from the anterior stem of the right coronary artery (but 35–45% arising from the circumflex branch of the left coronary artery), which runs around the base of the superior vena cava to reach the sinuatrial node. Syn: ramus nodi sinuatrialis arteriae coronaria dextra [NA], branch to sinuatrial node, sinuatrial nodal branch of right coronary artery, sinuatrial node artery.