Anomalous origin :- These include:

• The origin of the left main ( LM ), left anterior descending (LAD), left circumflex (LCx) or right coronary artery (RCA)from the pulmonary trunk (the left or right ventricles, the bronchial, internal mammary, subclavian, right carotid, or innominate arteries or the aortic arch or descending thoracic aorta);
• High takeoff of the left or right coronary ostia, defined as the location of the ostium of the left or right coronary artery more than 1 cm above the Sino-tubular junction.
• The anomalous location of the coronary ostium within the aortic root, near the proper aortic sinus of Valsalva (for each artery) or outside normal “coronary” aortic sinuses.
• The absent left main trunk (split origination of the left coronary artery (LCA).
  

• The LM originates from the RCA, or vice versa taking aberrant pathways;
• Separate origin of the LAD and LCx from the right coronary artery.
• Both the left and right coronary arteries may arise from a separate ostia located in the same, either left or right, sinus of the aorta.

Anomalous course and termination

• An intermyocardial ; course (i.e., the myocardial bridge).
  
  

Major epicardial coronary arteries may terminate abnormality into one of the cardiac chambers (the right or left atrium, the right or left ventricle), coronary sinus, superior vena cava, pulmonary artery, pulmonary vein and, thus, produce fistulas originating from:

• The left (50-60%);
• The right (30-40%);
• Or both (2-5% coronary artery systems.
  

Abnormal coronary structure

• A membrane or a fibrotic ridge usually causes congenital epicardial coronary artery stenosis
• Coronary artery atresia is characterized by the presence of an ostial dimple in the left or right aortic sinus that terminates in a patent lumen.
• Hypo plastic coronary arteries have a small luminal diameter (usually <1 mm ) and reduced length. The latter is often associated with the absence of the posterior descending coronary artery.
• Coronary ectasia or aneurysm.
  
  
• The absent coronary artery.