Left internal mammary artery--coronary artery bypass anatomy.

Bypass coronary surgery has made good use of the anatomic proximity of the internal mammary artery and the left anterior descending coronary artery. In preparing the internal mammary artery for bypass surgery, several of its proximal branches remain intact and are visualized during selective studies of the bypass graft. A brief description of these vessels is presented with specific attention to the branching and position of the pericardial vessels and their relationship to the grafted left anterior descending artery.