“…Although the adult heart normally contains a profusion of small interconnecting vessels between the two coronary arteries, they are not usually seen at angiography. However, when these direct anastomoses are large enough to be identified angiographically, they can be differentiated from collateral vessels on the basis of the prominent straight connection between the two unobstructed major arteries, often at or near the level of the crux, in contrast to the tortuous collateral vessels between the patent vessel and the obstructed vessel (46). Extracardiac Termination.-Connections may exist between the coronary arteries and extracardiac vessels (ie, the bronchial, internal mammary, pericardial, anterior mediastinal, superior and inferior phrenic, and intercostal arteries and the esophageal branch of the aorta) (13).…”