BLOOD-SUPPLY TO THE INTERVENTRICULAR SEPTUM OF THE HEART IN RODENTS WITH INTRAMYOCARDIAL CORONARY-ARTERIES

The blood supply to the interventricular septum of the heart was studied in a sample of 1634 specimens belonging to four rodent families, Cricetidae, Arvicolidae, Gliridae, and Muridae. Most specimens (n = 1604) were examined using a corrosion-cast technique, while the remaining 30 were studied by histological techniques. In 1417 cases the coronary artery pattern was normal, and the interventricular septum was fundamentally supplied by one or rarely two septal arteries arising from the right and/or left coronary arteries. In 72 specimens the right and left coronary arteries were normal, while the septal artery arose from a separate ostium in the aorta, behaving as a third coronary artery. The remaining 145 animals possessed anomalies in the origin of the coronary arteries, and the septum was also principally irrigated by a septal artery. In 5 of these 145 anomalous cases the septal artery originated from a separate ostium in the aorta. In all specimens examined a less important vascularization of the septum was established through thinner penetrating vessels originating from the right and/or left coronary arteries. Existence of one or rarely two septal arteries is the most constant feature of the coronary artery arrangement in rodents with intramyocardial coronary arteries.