Examples of antegrade coronary artery flow in the RCA and PDA. (A) In modified parasternal short-axis view searching the area adjacent to the right sinus of Valsalva the proximal right coronary artery (pRCA) is seen leaving the aortic root (Ao). (B) From subcostal modified sagittal view the pRCA is seen traversing caudally on the anterior tricuspid ring. (C) Using subcostal modified short-axis view parts of the middle segment of the right coronary artery (mRCA) are seen coursing medially on the medial tricuspid ring. (D) From modified apical 2-chamber view focusing on the posterior interventricular sulcus parts of the posterior descending coronary artery (PDA) are seen coursing toward the apex (Ax). L = liver; LA = left atrium; LV = left ventricle; RA = right atrium; RV = right ventricle.