a series of 80 heart dissections , compared with a survey of the literature shows that : -- both coronary ostia are usually in the right anterior and in the left posterior position , in the commissural plane , at the level of the corresponding sinus of valsalva ( the left one being often superior in size to the right one ) . -- anatomic variations of the coronary ostia ( especially variations of the left coronary ostium ) may be summed up into 3 patterns : variations in number : sometimes , there is only one aortic coronary ostium , usually owing to a left coronary artery originating from the pulmonary artery ;
C0018787
heart
C1261082
left