The importance of the coronary arteries for the nourishment of the heart is well known. The closure of one of the coronary arteries, by thrombosis or otherwise, is frequently the cause of sudden death. If death does not occur, necrosis of the part nourished by the occluded vessel takes place, followed by the development of a scar, and if this be extensive, aneurysm of the heart may form.
There are exceptions to this general statement with regard to the effects of occlusion of the coronary arteries. Many cases are reported which show that the main trunk of one of two coronary arteries may become plugged without causing sudden death. Such cases have been reported by Percy Kidd, Chiari and others. In these and similar cases it is presumed that the disastrous consequences usually observed failed to take place on account of anastomoses.
Anatomic investigations, especially studies of injected specimens, have