One hundred fifty‐four hearts were examined by postmortem coronary arteriography including ordinary and soft x‐ray exposure of the sliced hearts. Serial giant frozen sections of the entire heart were made to obtain the topographic view and quantitative observation of the ischemic lesions of the myocardium in connection with underlying changes of the coronary tree as well as electrocardiographic findings.Anatomical characterisitcs of the coronary arteries such as tortuousness and right angle ramification of the myocardial branches running toward cardiac lumen were demonstrated. Their endarteric nature at the level of functionally efficient terminal zone of the myocardial branches was pointed out and its important role in the development of ischemic lesions was discussed. The reason why the inner layers of the myocardial wall possesses much disadvantage of coronary circulation was clarified from the aspects of morphological findings and on some physiological considerations.The clinicopathological survey of the. cases indicated that the patients with hypertrophic hearts and coronary sclerosis are most vulnerable to the development of myocardial injury. The disadvantages of the hypertrophic state of the heart in the coronary circulation were emphasized.It was concluded that the myocardial injury is directly proportional to hypertrophy, hypertension, heart rate and coronary sclerosis. Based on the tension theories of the hypertrophic heart, the conclusion was theoretically confirmed to be reasonable. Myocardial injury index was suggested for practical use. ACTA PATH. JAP. 16:37‐54