Final answer:
The circumflex artery, a branch of the left coronary artery, supplies blood to the left atrium and the lateral and posterior sides of the left ventricle, as well as sometimes supplying the sinoatrial nodal artery.
Step-by-step explanation:
The circumflex artery is a significant branch of the left coronary artery that plays a key role in the coronary circulation of the heart. As it arises from the left coronary artery and follows the coronary sulcus, the circumflex artery primarily supplies blood to the left atrium, the lateral and posterior sides of the left ventricle, and the sinoatrial (SA) nodal artery in some individuals. The coronary arteries, including the circumflex artery, provide vital oxygenated blood to the myocardium, ensuring the heart functions effectively. Furthermore, the circumflex artery may anastomose with the branches of the right coronary artery or the posterior descending artery, contributing to the collateral circulation within the heart which is essential for maintaining blood flow in the event of blockages.