<P> The left coronary artery distributes blood to the left side of the heart , the left atrium and ventricle , and the interventricular septum . The circumflex artery arises from the left coronary artery and follows the coronary sulcus to the left . Eventually , it will fuse with the small branches of the right coronary artery . The larger anterior interventricular artery , also known as the left anterior descending artery ( LAD ) , is the second major branch arising from the left coronary artery . It follows the anterior interventricular sulcus around the pulmonary trunk . Along the way it gives rise to numerous smaller branches that interconnect with the branches of the posterior interventricular artery , forming anastomoses . An anastomosis is an area where vessels unite to form interconnections that normally allow blood to circulate to a region even if there may be partial blockage in another branch . The anastomoses in the heart are very small . Therefore , this ability is somewhat restricted in the heart so a coronary artery blockage often results in myocardial infarction causing death of the cells supplied by the particular vessel . </P>
where does the left coronary artery supply blood to
left side of the heart left atrium and ventricle interventricular septum