ABSTRACT
The first anterior septal arteries from 41 cadavers were studied. By the idealized classification they could be divided into 3 main types according to the path in the interventricular septum: Type I - 25 (60.98 per cent); Type II - 7(17.07 per cent); Type III - 9 (21.95 per cent). Several other parameters were studied regarding the 3 types: distance between the ostium and the bifurcation of the left coronary artery trnk; realtion with the second anterior septal artery; number of anterior septal arteries per heart; the greatest caliber of the anterior septal artery; relation of diameter with that of the anterior descending artery and angle of emergence at the anterior descending artery. These parameters were analyzed in view of a better knowledge about this coronary branch for surgery and clinical practice