There are two main arteries that lead to the heart, where each major artery branches into two smaller arteries, which makes a total of six, according to Cleveland Clinic. The blood vessels that supply the heart with oxygen-rich blood are referred to as coronary arteries.
The right coronary artery transports oxygenated blood to the right side of the cardiac muscle, which includes the right ventricle, right atrium, rear of the septum and base of both ventricles. This main artery is divided into two smaller branches: posterior descending and right marginal.
The left coronary artery provides blood to the left side of the heart, including the left ventricle, left atrium and the anterior portion of the septum. It also splits into two smaller branches: left anterior descending and circumflex, as explained by Cleveland Clinic.