Heart

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

Coronary Sinus

Coronary Sinus The structure indicated is the coronary sinus. 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. Learn more about the anatomy of the venous drainage of the heart in this tutorial.

Coronary Sinus

Left Anterior Descending Artery

Left Anterior Descending Artery The structure indicated is the left anterior descending artery (also known as the anterior interventricular artery). The left anterior descending artery is one of the coronary arteries which supplies the anterior and lateral parts of the myocardium and the interventricular septum. It is responsible for approximately 45-55% of the left ventricles blood supply. The left coronary artery 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 anterior descending artery itself has two different types of branches Septal branches …

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Left Anterior Descending Artery

Pulmonary Valve

Pulmonary Valve   The structure indicated is the pulmonary valve. 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 pulmonary valve (pulmonic valve) has three cusps. The pulmonary valve opens in ventricular systole, when the pressure in …

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Pulmonary Valve

Septal Papillary Muscle

Septal Papillary Muscle The papillary muscles are specialised structures in the ventricles which attach to the atrioventricular valves (tricuspid and mitral) via string-like extensions known as chordeae tendineae. They contract to prevent the atrioventricular valves from inverting and allowing blood to flow backwards into the atria. In the ventricles there are muscular ridges known as trabeculae carneae. Papillary muscles are specialised trabeculae carneae which are attached at one end to the ventricle wall, and at the other to the chordae tendineae. There are three papillary muscles in the right ventricle: anterior posterior septal These attach to the tricuspid valve. There …

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Septal papillary muscle highlighted in orange.