Anatomical Structure and Location of the Left Marginal Branch of the Circumflex Artery

Description

Shown from the left lateral aspect, the left ventricle dominates the inferior and lateral contour of the heart, with the left atrium positioned superior and posterior and the left auricle wrapping anteriorly near the base. The circumflex branch of the left coronary artery courses leftward in the atrioventricular (coronary) sulcus, then gives off the left marginal branch (obtuse marginal) that descends along the obtuse margin toward the apex on the lateral wall of the left ventricle. Superficial coronary veins accompany the arterial tree in the epicardial fat, with the great cardiac vein often tracking in the left atrioventricular groove near the circumflex before continuing toward the coronary sinus. This left-sided projection is the one you want when teaching or planning around obtuse marginal territory, because it clarifies which segments of the lateral left ventricle are supplied by circumflex-derived branches rather than the left anterior descending artery. In acute coronary syndrome, occlusion of the left marginal branch can produce lateral wall ischemia or infarction, reflected by ST-segment changes in leads I, aVL, V5, and V6, and it is a frequent target for bypass grafting or percutaneous coronary intervention. A practical landmark. The vessel’s relationship to the atrioventricular groove also matters during mitral valve surgery and left atrial procedures, where circumflex injury remains a recognized complication. Use this artwork for cardiothoracic anatomy lectures, interventional cardiology teaching files, and publisher figures explaining circumflex and obtuse marginal revascularization strategies, including CABG graft selection to the OM branches. It also fits radiology and cardiology materials that correlate epicardial coronary courses with CT coronary angiography or catheter angiographic projections. Anatomical accuracy verified by SciePro's Medical Advisory Board.