[Descriptive anatomical study of the major coronary trunks and the principal epicardial collaterals. 125 cases].

Abnormalities at the origin are rare and involve only the left coronary artery: absence of the trunk of this artery in 3 cases, as a result of separation of the origins of the anterior interventricular and the left circumflex. As far as course is concerned, the principal abnormality involves the anterior interventricular: presence in 17% of cases of an intraparietal segment, quite narrow and with a thin wall which is remarkably fixed and constant in its different characteristics: rapid reading of a film taken during selective injection may lead to a conclusion of stenosis or to that of a non-existent spasm. In 6% of cases, the posterior interventricular is short, joined to the middle part of the posterior interventricular sulcus by a collateral of the right coronary. Thus in the case of a long stenosis of the right coronary artery, right aorto-coronary by-pass, distal, provides no blood supply to the postero-inferior part of the septum and the posterior part of the apex. In more than one third of cases the left first diagonal and marginal arteries are of sufficient calibre to permit implantation of an aorto-coronary graft.