[Coronary arteries and their variations. An embryological explanation].

The main coronary arteries originate from three vascular circles: The atrioventricular circle, which forms the right coronary artery and the circumflex branch of the left coronary artery; the interampullary circle, which gives rise to the anterior and posterior descending coronary arteries; and the conotruncal circle, also known as the circle of Vieussens, which communicates with the lumen of the truncus arteriosus by way of the coronary ostia and which also anastomoses with the other two coronary arterial circles, thereby establishing the definitive coronary arterial circulation. A diagram facilitates an easy representation of the numerous variations of the coronary arteries that have been described.