The coronary system has been studied on the basis of 200 hearts taken during necropsies and treated by injection of a synthetic resin followed by corrosion. Sixty samples were used for the study of the L.A.D. and one hundred and fifty were used for studying intercoronary anastomosis on L.A.D. The study highlighted the following particularities: the left coronary is the most common origin of L.A.D. (90 per cent cases); the L.A.D. irrigates: all the left ventricle ventral wall, the right apical part of both ventricles and the upper portion of the interventricular septum; out of 92 anastomoses, 49 were located on the L.A.D. which could protect against ischemia.