Blood supply of the human interventricular septum in north-west Indians.

The blood supply of the human interventricular septum was studied in hearts obtained from 500 (300 males and 200 females) medicolegal autopsy subjects aged 18 to 75 years. In 350 specimens the coronary arteries were injected with 20 per cent solution of cellulose acetate butyrate and branches supplying the septum were displayed by dissection while in the remaining hearts the arteries were injected with a solution of barium sulphate and X-rays taken. The anterior two-thirds of the septum is supplied by 4 to 10 perforators and one or two long septal arteries (in 94 per cent instances) which arise from the anterior interventricular artery; the latter turns round the inferior border of the heart and extends for a variable distance in the caudal part of the interventricular sulcus and supplies perforators to the posterior one-third of the septum. The cephalic part of the posterior one-third of the septum gets its blood supply from the posterior interventricular artery; some variations in this arrangement have been encountered. In about 85 per cent instances the right coronary artery or its conus branch gives an interventricular septal branch which pierces the anterior wall of the right ventricle and runs subendocardially on the supraventricular crest to reach the interventricular septum where it anastomoses with the anterior perforators; about 15 per cent subjects who do not have this septal branch are likely to sustain a larger infarction in case the anterior interventricular artery gets blocked.