The Left Surface of the Heart

Description

Oriented to the patient’s left, the left surface of the heart is formed predominantly by the left ventricle, with the left atrial appendage draping anterosuperiorly near the root of the pulmonary trunk. The left border (margo obtusus) curves inferolaterally toward the apex, while the base sits superior and posterior where the left atrium receives the pulmonary veins. Coronary vessels course in their expected grooves, with the circumflex branch of the left coronary artery and the great cardiac vein tracking along the left atrioventricular (coronary) sulcus, and diagonal branches crossing the anterolateral left ventricular myocardium. Surrounding thoracic context places the heart posterior to the sternum and costal cartilages, anterior to the vertebral column, and medial to the left lung. This surface matters because it aligns with the lateral wall of the left ventricle, the territory often supplied by the left circumflex artery (or obtuse marginal branches) and a common site of ischemia in lateral STEMI patterns. Correlating the margo obtusus and the course of the circumflex helps during coronary angiography, minimally invasive lateral approaches, and pericardial access planning when the left phrenic nerve and pericardiophrenic vessels run along the fibrous pericardium nearby. A key landmark. Use this artwork for gross anatomy and cardiothoracic surgery teaching when you want students to reconcile external cardiac morphology with coronary perfusion territories, or for textbooks and journal figures discussing lateral wall infarction, mitral valve surgery exposure, and coronary artery bypass targets on the obtuse marginal system. It also reads well in patient-facing educational materials that explain why left-sided chest pain can reflect myocardial ischemia rather than lung pathology. Anatomical accuracy verified by SciePro's Medical Advisory Board.