The human hart is in most cases vascularized by two coronary arteries, the right and the left one. Supernumerary or added coronary arteries are also present sometimes. The aim of this paper is to ascertain presence of supernumerary coronary arteries that arise directly from aorta, their frequency, flow, way of branching, and possibly their anastomoses with other coronary arteries. Out of 25 hearts, examined by dissection, 8 of them (32%) had conal artery. According to our opinion, the most suitable term for this artery, in order to differ it clearly from the conal branch of the right coronary artery, is third coronary artery. One heart (4%) had four coronary arteries. Both supernumerary coronary arteries arose from the right aortic sinus. The third coronary artery represents a significant way of collateral coronary circulation, as it frequently anastomoses with anterior interventricular branch.

Proficiency in the anatomy of coronary arteries and their variations is significant for proper interpretation of the coronary angiographies, assessment of the complexity and result of the coronary insufficiency as well as surgical myocardium revascularization. The objective of this study is anatomy-radiology research of the methods of branching the main trunk of left coronary artery and to prove importance of the diagonal branch (ramus diagonalis) existence in the conditions of coronary insufficiency. In this study we have analyzed 100 coronary angiographies done at the Clinic for Heart Diseases and Rheumatism of the Clinic Center of University of Sarajevo and dissected 20 human hearts from the Institute of Anatomy. In our study we have come upon two methods of branching of main trunk of left coronary artery (bifurcation and trifurcation). By the method of the angiography we have found the bifurcation in 71% of cases while 65% of cases were proved by the dissection method. Trifurcation has been discovered in 29% of cases of analyzed angiographies i.e. 35% of cases of dissected hearts. We believe that third terminal branch of the left coronary artery should be marked as ramus diagonalis. This branch, including its anastomoses, presents important pattern of the collateral blood flow, which has special meaning, under conditions of coronary insufficiency.