During the dissection of the heart of an 86-year-old male cadaver a relatively larger left coronary artery was incidentally detected. This artery divided into anterior interventricular and circumflex branches as usual, and the circumflex branch further divided into SA-nodal branch, left atrial branches, left marginal branch and left ventricular branches. As the circumflex branch coursed through the posterior aspect of the coronary sulcus it became covered by myocardial bridge and tunneled through the myocardium which it exited near the crus. Then it gave branch to the AV-nodal branch, right atrial branch, left and right ventricular branches, and the posterior interventricular artery. The smaller right coronary artery supplied only the sternocostal aspects of the right atrium and ventricle. Since such variant intramyocardial course may be associated with significant acute coronary syndrome or sudden death, every clinician should be aware of myocardial bridges particularly in condition refractory to medical and surgical treatment.
