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    From Cardiovascular System

    External Iliac Arteries
    Continue into the legs as femoral arteries.
    Subclavian Veins
    Carry blood from the upper limbs to the heart.
    Abdominal Aorta
    Part of descending aorta within the abdomen.
    Left Atrium
    Receives oxygenated blood from the lungs.
    Interatrial Septum
    Wall separating the left and right atria.
    Ascending Aorta
    Initial portion of the aorta emerging from the heart.
    External Carotid Artery
    Supplies blood to the face and scalp.
    Superior Vena Cava
    Returns deoxygenated blood from upper body.
    Moderator Band
    Muscular band of heart tissue found in the right ventricle.
    Papillary Muscles
    Muscles that anchor the heart valves via chordae tendineae.
    Posterior Tibial Arteries
    Supply posterior compartment of the leg.
    Trabeculae Carneae
    Irregular muscular columns on the walls of the ventricles.
    Pulmonary Trunk
    Carries deoxygenated blood from right ventricle to lungs.
    Small Saphenous Vein
    Superficial vein of the posterior leg.
    Left Pulmonary Artery
    Carries blood to left lung.
    Pericardium
    Double-walled sac containing the heart and the roots of the great vessels.
    Left Superior Pulmonary Vein
    Returns oxygenated blood from left lung.
    Right Pulmonary Artery
    Carries blood to right lung.
    Internal Carotid Artery
    Supplies blood to the brain.
    Left Subclavian Artery
    Supplies the left upper limb.
    Femoral Arteries
    Main arteries supplying the thighs.
    Right Inferior Pulmonary Vein
    Returns oxygenated blood from right lung.
    Fossa Ovalis
    Remnant of the fetal foramen ovale.
    Marginal Branch
    Supplies right ventricle along the margin.
    Axillary Veins
    Drain the upper limbs and join with subclavian veins.

    Circumflex Branch

    Reviewed by our medical team

    Curves around to the posterior heart.

    1. Overview

    The circumflex branch (also known as the left circumflex artery or LCX) is one of the primary branches of the left coronary artery (LCA), which originates from the ascending aorta. It plays a key role in supplying oxygenated blood to the left side of the heart, particularly the left atrium, the left ventricle, and parts of the interventricular septum. The circumflex artery branches off from the left coronary artery shortly after its origin and wraps around the left side of the heart, following the coronary sulcus (the groove between the atria and ventricles). The circumflex artery is critical for maintaining the blood supply to the heart muscle and supporting proper cardiac function.

    2. Location

    The circumflex branch is located in the coronary sulcus, which is the groove that separates the atria from the ventricles. After arising from the left coronary artery, it travels toward the left side of the heart, wrapping around the atrioventricular groove. The circumflex artery runs along the posterior part of the heart, giving off several branches that supply blood to the left atrium, the lateral and posterior walls of the left ventricle, and parts of the interventricular septum. In some individuals, the circumflex artery may also contribute to supplying blood to the posterior portion of the heart, depending on the coronary anatomy.

    3. Structure

    The circumflex artery is a medium-sized artery with a robust structure designed to withstand the high pressure of blood flow from the left ventricle. Some key structural features of the circumflex branch include:

    • Origin: The circumflex artery originates from the left coronary artery, just after the left coronary artery arises from the ascending aorta. It is one of the two major branches of the left coronary artery, with the other being the left anterior descending (LAD) artery.

    • Course: The circumflex artery follows the coronary sulcus around the left side of the heart. It then curves around the posterior aspect of the heart to supply blood to the left atrium, left ventricle, and parts of the interventricular septum.

    • Branching: The circumflex artery gives off several important branches, including:

      • Left marginal artery: This branch supplies the lateral wall of the left ventricle.

      • Posterior left ventricular artery: In some individuals, the circumflex artery gives rise to this branch, which supplies blood to the posterior part of the left ventricle.

      • In some cases, the posterior descending artery: In certain coronary anatomies, the circumflex artery may give rise to the posterior descending artery, which supplies the posterior part of the interventricular septum.

    • Diameter: The circumflex artery is typically 2-4 millimeters in diameter, though its size can vary depending on the individual and the dominance of the coronary circulation.

    4. Function

    The primary function of the circumflex artery is to supply oxygenated blood to the heart muscle, particularly the left atrium, the left ventricle, and the posterior and lateral walls of the heart. Some key functions of the circumflex artery include:

    • Supplying blood to the left atrium and ventricle: The circumflex artery is responsible for delivering oxygen-rich blood to the left atrium and the lateral and posterior walls of the left ventricle. These regions are critical for maintaining proper cardiac function, as the left ventricle pumps oxygenated blood throughout the body.

    • Supporting myocardial function: By supplying blood to the myocardium (heart muscle), the circumflex artery plays a crucial role in ensuring that the heart receives the oxygen and nutrients required for contraction. This is essential for maintaining heart rhythm, muscle strength, and overall function.

    • Supplying blood to the interventricular septum: The circumflex artery also provides blood to parts of the interventricular septum (the wall between the left and right ventricles). This is important for maintaining the structure and function of the septum, which is responsible for proper ventricular contraction and coordination.

    5. Physiological Role(s)

    The circumflex artery has several important physiological roles that are essential for maintaining normal heart function and overall cardiovascular health. Some of its key physiological roles include:

    • Blood supply to the left heart structures: The circumflex artery ensures that the left atrium and left ventricle receive a continuous supply of oxygenated blood. This is critical for maintaining the efficiency of the heart’s pumping action, as the left ventricle is responsible for delivering blood to the systemic circulation.

    • Facilitating cardiac function during physical exertion: During exercise or stress, the body requires more oxygen and nutrients to meet the increased metabolic demands of the heart. The circumflex artery helps provide this increased blood supply to the heart muscle, ensuring that it can contract effectively and meet the increased demands for oxygenated blood.

    • Supporting electrical activity of the heart: By supplying blood to the tissues involved in generating and conducting electrical impulses in the heart, the circumflex artery plays a role in maintaining the proper rhythm and conduction of electrical signals, ensuring coordinated heartbeats and efficient contraction.

    6. Clinical Significance

    The circumflex artery is clinically significant due to its crucial role in supplying blood to the left side of the heart. Various cardiovascular conditions can affect the circumflex artery, leading to reduced blood supply to the heart muscle and increasing the risk of heart disease. Some of the key clinical conditions associated with the circumflex artery include:

    • Coronary artery disease (CAD): Atherosclerosis, or the buildup of fatty deposits and plaque in the coronary arteries, can affect the circumflex artery, narrowing or blocking the artery and reducing blood flow to the heart muscle. CAD can result in chest pain (angina), shortness of breath, or heart attacks (myocardial infarctions) if the blood flow is significantly reduced or blocked. Treatment may involve lifestyle changes, medications, or surgical interventions such as angioplasty or coronary artery bypass grafting (CABG).

    • Myocardial infarction (heart attack): If the circumflex artery becomes severely blocked, it can lead to a heart attack, particularly affecting the left ventricle and the posterior part of the heart. A blockage in this artery may result in ischemia (lack of oxygen) to the heart muscle, leading to tissue death and impaired cardiac function. Immediate medical attention is required, and interventions like thrombolysis or coronary artery bypass surgery may be necessary.

    • Ischemic heart disease: Chronic reduction in blood supply due to blockages or narrowing in the circumflex artery can lead to ischemic heart disease. This condition is characterized by persistent chest pain, fatigue, and reduced exercise tolerance. It can be managed with medications such as nitrates, beta-blockers, or angioplasty to restore blood flow.

    • Left ventricular dysfunction: Since the circumflex artery supplies blood to the left ventricle, blockage or narrowing of this artery can lead to left ventricular dysfunction, resulting in symptoms such as fatigue, fluid retention, and shortness of breath. In severe cases, it may contribute to heart failure, where the heart is unable to pump blood efficiently to the rest of the body.

    • Coronary artery spasm: A spasm in the circumflex artery, known as a coronary spasm, can cause temporary narrowing or closure of the artery, leading to reduced blood flow to the heart. This can result in chest pain (Prinzmetal angina) and may increase the risk of heart attacks if left untreated. Medications such as calcium channel blockers may be used to treat this condition.

    The circumflex artery plays a vital role in maintaining the blood supply to the left side of the heart and is crucial for cardiac function. Blockages, narrowing, or other dysfunctions in the circumflex artery can lead to severe cardiovascular complications, including coronary artery disease, myocardial infarction, and heart failure. Early diagnosis, lifestyle changes, and appropriate treatment are essential for managing these conditions and ensuring optimal heart health.

    Did you know? A stroke happens when a blockage or rupture disrupts the normal flow of blood to the brain.