Mediastinum

Left Coronary Artery

Left Coronary Artery The structure indicated is the left coronary artery. The left coronary artery (LCA) arises from the left aortic sinus of the ascending aorta. The left coronary artery has two terminal branches: Left anterior descending (LAD)/anterior interventricular Circumflex branch The left circumflex artery (LCX) supplies blood to the posterolateral left ventricle as well as the anterolateral papillary muscle and provides part of the supply to the left ventricle. The left anterior descending artery also supplies the left ventricle, and is responsible for the arterial supply to the anterolateral myocardium, the apex of the heart and the interventricular septum. …

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left coronary artery

Small Cardiac Vein

Small Cardiac Vein The structure indicated is the small cardiac vein. The coronary sinus lies posteriorly on the heart in the coronary sulcus and receives four cardiac veins: Great cardiac vein Middle cardiac vein Small cardiac vein Posterior cardiac veins The coronary sinus returns deoxygenated blood to the right atrium of the heart, together with the superior and inferior vena cavae. The small cardiac vein lies in the coronary sulcus between the right atrium and the right ventricle. Learn more about the blood supply to the heart in this tutorial.

Right Coronary Artery

Right Coronary Artery The structure indicated is the right coronary artery of the heart. The coronary arteries arise from the aortic sinuses of the ascending aorta. The right coronary artery (RCA) arises from the right aortic sinus and the left coronary from the left aortic sinus. The right coronary artery then runs in the coronary sulcus, which separates the atria from the ventricles. The right coronary artery gives off the following branches: Atrial arteries Right marginal branch Posterior interventricular branch (posterior descending artery) The coronary artery from which the posterior descending artery arises determines the coronary dominance. The posterior descending artery …

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right coronary artery

Atrioventricular Node

Atrioventricular Node The structure indicated is the atrioventricular node. The conduction system of the heart is responsible for the synchronised contraction of the atria and ventricles and is comprised of the following main structures: Sinoatrial node Atrioventricular node Atrioventricular bundle of His Right and left bundle branches Purkinje fibres The atrioventricular node is located centrally in the Triangle of Koch, between the atria and ventricles in the infero-posterior portion of the interatrial septum close to the opening of the coronary sinus. The triangle of Koch has the following boundaries: Ostium of coronary sinus Tendon of Todaro Anterior-septal leaflet commissure The …

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atrioventricular node

Sinoatrial Node

Sinoatrial Node The structure indicated is the sinoatrial node The conduction system of the heart is responsible for the coordinated contraction of the atria and ventricles and is comprised of the following main structures: Sinoatrial node Atrioventricular node Atrioventricular bundle of His Right and left bundle branches Purkinje fibres The sinoatrial node, often referred to as the SA node, is the pacemaker of the heart. It is located in the right atrium and is responsible for generating normal sinus rhythm. The sinoatrial node is located lateral to the junction where the superior vena cava enters the right atrium. Electrical signals generated …

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sinoatrial node

Aortic Arch

Aortic Arch The structure indicated is the arch of the aorta. The aorta arises from the left ventricle of the heart and supplies the body with oxygenated blood. The aorta can be divided into thoracic and abdominal parts (the thoracic aorta pierces the diaphragm to enter the abdominal cavity, becoming the abdominal aorta). The thoracic aorta consists of: Ascending aorta Aortic arch Descending (thoracic) aorta The aortic arch lies in the superior mediastinum and begins and ends at the level of the angle of Louis (sternal angle) which lies at the level of the intervertebral disc between T4/T5. The arch …

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aortic arch

Tricuspid Valve

Tricuspid Valve The structure indicated is the tricuspid valve of the heart. There are four sets of valves in the heart. Between the atria and the ventricles are the atrioventricular valves; on the right is the tricuspid valve, on the left is the mitral (bicuspid) valve. Between the ventricles and the aorta/pulmonary trunk are the semilunar valves. The pulmonary valve is located between the right ventricle and the pulmonary trunk, and the aortic valve is located between the left ventricle and the aorta. The atrioventricular valves are controlled by papillary muscles, which are specialised structures in the ventricles that attach …

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Tricuspid Valve

Great Cardiac Vein

Great Cardiac Vein The structure indicated is the great cardiac vein. The coronary sinus lies posteriorly on the heart in the coronary sulcus and receives four cardiac veins: Great cardiac vein Middle cardiac vein Small cardiac vein Posterior cardiac veins The great cardiac vein lies in the anterior interventricular sulcus together with the anterior interventricular artery (left anterior descending), and for this reason it is sometimes referred to as the anterior interventricular vein. The great cardiac vein begins at the apex of the heart and ascends in the anterior interventricular sulcus to reach the coronary sulcus, where it then runs …

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Great Cardiac Vein

Posterior Interventricular (Descending) Artery

Posterior Interventricular (Descending) Artery The structure indicated is the posterior interventricular artery (posterior descending artery) of the heart. The posterior interventricular artery determines the “dominance” of the coronary blood supply to the heart. For example, if the posterior interventricular artery arises from the right coronary artery, the heart is said to be “right coronary dominant”. In the majority of people, the posterior interventricular artery will usually arise from the right coronary artery. If the posterior interventricular artery arises from the left coronary artery, it will branch from the circumflex coronary artery. Co-dominance occurs when the posterior interventricular artery arises from …

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Posterior Interventricular (Descending) Artery