Rare case of single left coronary artery in a Japanese cadaver.

A single left coronary artery with a single orifice in the left aortic sinus was observed during anatomical practice in an 81-year-old male Japanese cadaver. The single left coronary artery bifurcated into the anterior interventricular branch (IVa) and circumflex (CXa) branches. The IVa descended into the anterior interventricular sulcus to supply the apex of the heart, leaving a branch that traversed the upper part of the infundibulum to supply the anterior upper region of the right ventricle. The CXa curved leftward in the atrioventricular sulcus to reach the posterior surface, after which it continued to emerge into the anterior surface. The vascular running pattern showed that CXa directly supplied blood to the upper right ventricle (but not the conus branch), with three branches connected to the apex. The atrial arteries showed no anomalous distribution patterns. These findings are useful during surgical procedures, including cardiac catheterization.