Variations in the relationship of the major vessels of the left coronary groove in the dog.

The anatomic relationship of the 2 major vessels of the left coronary groove was studied in 140 dogs. Five basic patterns of disposition were observed: 1) circumflex artery superficial from its origin to the caudodorsal cardiac margin, coronary vein deep and not visible (22%); 2) coronary vein superficial from the ventral interventricular septum to the caudodorsal cardiac margin, circumflex artery deep and not visible (15%); 3) circumflex artery and coronary vein both superficial and running parallel with each other along the groove (8%); 4) coronary vein crossing circumflex artery at some point along the groove (44%); and 5) circumflex artery crossing coronary vein at some point along the groove (11%). These variations were found to influence certain experimental modifications of the left circumflex blood flow in the dog.