The present work is aimed to study the distribution of the coronary arteries to the left ventricle; 120 fresh and prepared human hearts harvested from healthy individuals of both sexes aged 4 to 78 have been used. The denomination of the cardiac segments is the one used by Liberato, Didio & Rodrigues in 1983. Starting from this model, we sought for sustaining or invalidating arguments. We used special dissection techniques, radiographs of radioopaque substances injected hearts, and corroded after plastic substances injection organs. Each ventricular segment in the left ventricle is supplied by an arterial branch (called "segmental") of the coronary arteries (left coronary artery in most of cases). The anterior interventricular branch segment (I SV or SVIA) is the area of the heart supplied by the arterial branch with the same name, originating in the left coronary artery. Depending on its length, we found a small segment (the branch did not pass over the apex of the heart, thus supplying the sternocostal surface of the heart only) in 39 cases (32.5%), and a big segment (the artery ended on the diaphragmatic surface of the heart, in the posterior interventricular groove) in 81 cases (67.5%). The lateral branch segment (II SV or SVL) includes in most of cases (78%) a part of the pulmonary wall of he left ventricle, up to the apex (Liberato et al. found a percent of 66). In the rest of cases (22%) it additionally includes a part of the diaphragmatic wall of the left ventricle. The left marginal branch segment (III SV or SVM) is a big one when it includes parts of the pulmonary and diaphragmatic walls of the left ventricle and part of the diaphragmatic wall of the right ventricle; it is middle-sized when it includes parts of the left and diaphragmatic walls of the left ventricle; it is considered small when it extends over parts of the left and diaphragmatic walls of the left ventricle adjacent to the pulmonary surface (36%, 40% and 24% of cases, respectively). The posterior ventricular branch segment (IV SV or SVP) includes: a small part of the diaphragmatic wall of the left ventricle close to the pulmonary surface--52 cases (43.3%); the superior half of the diaphragmatic wall of the left ventricle up to the posterior interventricular septum--19% of cases; the superior third of the left ventricle, up to the septum--20% of cases; the superior part of the diaphragmatic wall of both ventricles and the superior part of the septum--13.6% of cases. The segments are separated by intersegmental planes whose position depends of the degree of development of each cardiac segment. No significant differences were observed in what concerns the extension of the cardiac segments and the position of intersegmental planes in relation to sex. The segments can be totally independent or slightly dependent to the blood supply of the neighbouring segments.