Blood supply of the human interventricular septum.

The blood supply of the interventricular septum has been studied in 43 normal human hearts, from patients dying of noncardiac causes. The specimens were prepared by injection of vinylite into the coronary arteries. Description is made of the normal vascular anatomy of this area, and its clinical importance is discussed. A LTHOUGH the interventricular septum comprises a large portion of the myo-cardium, study and description of its normal blood supply have been neglected; one standard textbook of anatomy fails even to mention it.' This lack of attention may be attributed to its relative inaccessibility for anatom-ic studies without disturbing its structural relationships. Injection of colored opaque solutions , followed by clearing in various oils, fails to display the interventricular septum adequately.2' 3 Stereoscopic roentgenograms of injected coronary arteries result in overlapping of septal vessels to such an extent that their individual identification becomes difficult , if not impossible.3 "Unrolling" the heart before the roentgenograms are taken4 isolates the septum but also removes it from its spatial orientation. Laubry, Soulie, and Thys5 injected radio-paque material into the coronary arteries and then obtained roentgenograms of the isolated interventricular septum, whereas HermanekM examined the blood supply of this region by dissection alone; both these studies, however, were concerned primarily with infarction and coronary anastomoses in the septum. For examination of the normal blood supply of the heart a more satisfactory method is injection of a noncorroding substance into the arteries, followed by corrosion of the supporting structures to leave a cast of the arteries. Additional casts of the cardiac chambers result in a spatially oriented replica of the en-391 tire heart. Casting of the chambers of only one side of the heart makes possible examination of the vessels in the interventricular sep-tum. This method was employed in the present study to obtain information regarding the normal blood supply of the human interven-tricular septum. MATERIAL AND METHODS Forty-three human hearts, of patients (32 men and 11 women) who died of noncardiac causes, were examined. Ages ranged from 12 to 81 years, with similar frequency distribution in each decade except for the eighth and ninth decades of life, which contained 1 patient each. These hearts were normal in weight and the ventricles on gross inspection were not hyper-trophied. In all hearts the valves were examined under direct vision through the aorta, main pulmonary artery, venae cavae, and pulmonary veins; in this series none of the …