Superior Vena Cava

(SVC)

A vein that carries blood from the upper half of the body to the heart's right atrium.

The SVC is formed by the union of the Right Brachiocephalic and Left Brachiocephalic veins superiorly,

and the azygous vein dorsally.

Surrounding Structures: Arch of aorta (Left), Heart (Inferior)

May be confused with Arch of aorta. The SVC is distinguished by its relatively short length (after the union of brachiocephalic veins), and its connection with the right atrium.

Inferior Vena Cava

(IVC)

A vein that carries blood from the lower half of the body to the heart's right atrium.

The IVC travels on the right side of the vertebral bodies and enters the heart at the lower right side.

The IVC anastomoses with the azygous vein, is located posterior to it.

The IVC may not be immediately identifiable if the heart has not been removed. The IVC forms a prominent opening through the pericadium inferiorly.

Surrounding Structures:Azygous Vein (posterior), Heart (Superior), Right lung (right)

May be confused with Azygous vein. Although the IVC anastomoses with the azygous vein, it is wider and more prominent than the azygous vein. The IVC enters the right atrium inferiorly, while the azygous vein does not.

Right Superior and Inferior Pulmonary Veins

These veins carry oxygenated blood from the their respective lobes of the right lung to the left atrium.

In the lungs, they do not follow the branching of the bronchial tree.

Surrounding Structures on the heart and interior pericardium: Inferior Vena Cava (Inferior), Superior Vena Cava (Superior)

May be confused with left pulmonary veins on heart and interior pericardium. The right pulmonary veins are located between the openings of the inferior vena cava and superior vena cava.

Surrounding Structures on the right lung hilum: bronchiopulmonary lymph nodes, right pulmonary arteries, right intermediate or secondary bronchus

May be confused with everything on the right hilum. The right pulmonary veins are not surrounded by thick cartilage indicative of the bronchus, and do not follow the branching pattern of the bronchus.

These veins carry oxygenated blood from the their respective lobes of the left lung to the left atrium.

In the lungs, they do not follow the branching of the bronchial tree.

Surrounding Structures on the heart and interior pericardium: Bifurcation of Pulmonary Trunk (Superior)

May be confused with right pulmonary veins on heart and interior pericardium. The left pulmonary veins are located on the left side and inferior to the pulmonary trunk.

Surrounding Structures on the left lung hilum: bronchiopulmonary lymph nodes, left pulmonary arteries, left intermediate or secondary bronchus

May be confused with everything on the left hilum. The left pulmonary veins are not surrounded by thick cartilage indicative of the bronchus, and do not follow the branching pattern of the bronchus.

Oblique Sinus

The Oblique Sinus is a cul-de-sac formed behind the left atrium by the reflection of the serous pericardium around the large veins. It is filled with pericardial fluid.

Surrounding Structures: Left pulmonary veins (left), Right pulmonary veins (right), esophageal prominence (along pericardium)

May be confused with Transverse Sinus. The Oblique sinus is located inferior to the transverse sinus and can be felt by placing a few fingers under and behind the heart (before it is removed). It marks the Outflow-pathway.

The transverse sinus is posterior to the ascending aorta and pulmonary trunk. It is fulled with pericadial fluid.

Surrounding Structures: Ascending aorta (superior), pulmonary trunk (superior), Oblique sinus (inferior)

May be confused with Oblique Sinus. The Transverse sinus is located superior to the oblique sinus and can be felt by placing a finger behind the pulmonary trunk and ascending aorta (before the heart is removed). It marks the inflow-pathway.

The right coronary artery and its branches supply the right atrium and ventricle as well as most of the initial portions of the conducting system of the heart. Most of the blood flows into this vessel during diastole.

Along with the right coronary veins, it runs along the coronary (atrioventricular) sulcus.

Originates from: the dilated region of the ascending aorta (aortic sinus).

Branches into: Artery of the sinus node, marginal artery, posterior interventricular artery

Surrounding structures: Arch of aorta (superior), Right auricle (superficial), right atrium (right), right ventricle (left, towards apex)

May be confused with left coronary artery. Easily distinguished by overlying (superficial) right auricle and superior arch of aorta.

Right dominance:  If posterior descending (interventricular) artery is a branch of the right coronary, the heart is said to be 'right dominant.'

Separates the atria and ventricles of the heart.

Nearby structures: Right coronary artery (runs along its length), right auricle (superior and superficial)

Maybe confused with interventricular sulcus, which is located closer to the apex. The Atrioventricular Sulcus is closer to the Superior Vena Cava.

A branch of the right coronary artery that supplies the right ventricle.

Surrounding structures: Right ventricle (deep)

May be confused with: Various cardiac veins. The right marginal branch is easily identified as the longest branch of the right coronary artery that travels along the right ventricle towards the apex.

Artery which runs along the posterior interventricular sulcus. It may arise from the right coronary artery or the left coronary artery, defining the dominace of the heart. It supplies and separates the ventricles.

Anastomoses with: circumflex branch of left coronary artery

Surrounding strucutres: ventricles, interventricular sulcus (deep)

May be confused with middle cardiac vein. The interventricular branch arises from the right coronary artery, while the middle cardiac vein leads to the coronary sinus.

Originates from the dilated region of the ascending aorta, the aortic sinus. Like the right coronary artery, most of the blood flows into this vessel during diastole.

Two major branches: Anterior descending and the circumflex artery (which in turn gives off the left marginal).

Surrounding Structures: Ascending aorta (at beginning)

May be confused with: Great Cardiac Vein. Great cardiac vein travels with the anterior descending branch, but does not originate from aorta.

Left dominance: Left dominance arises if the posterior descending artery is a branch of the left coronary artery. An individual with left dominance will be severely compromised if the left coronary artery is diseased because neither the posterior descending nor the anterior descending arteries will supply the ventricles or the interventricular septum.

Anterior Descending (Interventricular branch), Left Coronary Artery

(LAD)

This artery runs in the interventricular sulcus, supplying both ventricles, and is generally the first branch of the left coronary artery. It gives rise to the interventricular septal branches.

Begins at: left coronary artery

Surrounding structures: Left and right ventricles, interventricular sulcus (deep), Great cardiac vein

May be confused with: Great Cardiac Vein. The Left anterior descenting artery arises from the left coronary artery (which arises from the ascending aorta. The great cardiac vein arises from the coronary sinus.

Pathology: Because the LAD provides much of the bloodflow for the left ventricle, blockage of this artery severely disrupts blood flow through the aorta, leading to massive ischemia. Such myocardial infarctions are referred to as 'widowmakers.'

These are the grooves separating the ventricles from eachother.

The posterior interventricular sulcus is at the diaphragmatic surface of the heart and contains the posterior descending (interventricular) artery and the middle cardiac vein.

The anterior interventricular sulcus is at the sternocostal surface of the heart and contains the left anterior descending (interventricular) artery and the great cardiac vein.

Artery which branches off the left coronary artery and travels to the posterior aspect of the heart, where it anastomoses with the right coronary artery.

This artery immediately gives rise to the left marginal artery, which supplies the lateral wall of the left ventricle.

Surrounding structures: Left Auricle (superficial), great cardiac vein (from coronary sinus)

May be confused with: left marginal artery. The circumflex artery remains superior to the left marginal, which branches and immediately travels towards the apex. The circumflex branch, instead travels along the left auricle before it crosses the great cardiac vein (from the cardiac sinus) and travels towards the apex.

This vein begins at the apex of the heart and ascends along the anterior interventricular sulcus, under the left auricle, and posteriorly to join the coronary sinus.

The Great Cardiac vein recieves blood from the left atrium and both ventricles.

Surrounding structures: Left auricle (superior), anterior interventricular sulcus (deep)

May be confused with: Left anterior (interventricular) descending coronary artery. The Great Cardiac vein travels posteriorly towards the cardiac sinus, not laterally towards the left coronary artery and ascending aorta.

Travels from the apex of the heart at the posterior aspect directly superior (and along the posterior interventricular sulcus) towards the Coronary Sinus.

May be confused with: Posterior descending (interventricular) right coronary artery. Middle Cardiac Vein empties into the cardiac sinus, not the right coronary artery.

Major vein located on posterior aspect of heart. Opens directly into the right atrium.

Recieves blood from: Great Cardiac Vein, Middle Cardiac Vein, and Small cardiac vein

Opening from the Superior Vena Cava viewed from inside the right atrium of the heart. Brings deoxygenated blood from the upper body to the heart.

Surrounding structures: Orifice of Inferior Vena Cava (Inferior)

May be confused with: Orifice of Inferior Vena Cava. The Superior orifice is located at the superior aspect of the atrium.

Opening from the Inferior Vena Cava viewed from inside the right atrium of the heart. Brings deoxygenated blood from the lower body to the heart.

Surrounding structures: Orifice of Superior Vena Cava (Superior), Opening of Coronary Sinus

May be confused with: Opening of Coronary Sinus. The orifice of the inferior vena cava is wider in diameter and seperated from the right atrium by a valve.

Smallest hole seen from inside of the right atrium of heart. Carries deoxygenated blood from coronary veins.

Surrounding structures: Orifice of Inferior Vena Cava, Septal Cusp of tricuspid valve

May be confused with: Orifice of Inferior Vena Cava. The Opening of the coronary sinus is smaller in diameter than that of the Inferior vena Cava and is located closer to the tricuspid valve.

A smooth muscular ridge located inside the right atrium that extends from the openings of the superior and inferior vena cava. It separates the anterior and posterior walls of the right atrium.

Surrounding structures: Pectinate Muscles

May be confused with: Pectinate Muscles. The pectinate muscles which line the anterior wall of the right atrium terminate at the crista terminalis.

Elevation in the musculature of the anterior wall of the right atrium. These elevations terminate at the crista terminalis.

A feature of the interatrial septum. It is an embryonic remnant of the foramen ovale.

Pathology: Failure of the foramen ovale to close results in patent foramen ovale, a defect which causes oxygenated blood from the left atrium to flow into the right atrium.

Most individuals with atrial septal defects (ASD) are asymptomatic, but if the hole is large enough, there is an enlargement of the chambers on the right side of the heart and enlargement of the pulmonary trunk.

Atrioventricular (Tricuspid) Valve

Separates the right atrium and right ventricle, preventing regurgitation of blood into the right atrium during systole. Consists of three leaflets and three papillary muscles (anterior, posterior, and septal) that are joined to the right atrial wall by the chordae tendineae.

Pathology: The tricuspid valve is often affected by rheumatic fever and certain congenital problems. The regurgitation of blood into the right atrium may cause distended jugular veins and right sided heart failure.

Auscultation: The tricuspid area is at the lower left sternal margin - associated murmurs can be heard here.

May be confused with: Mitral Valve. The Tricuspid valve is located on the right side of the heart!

An appendage of the right atrium. It is visualized clearly from the anterior side, inferior to the superior vena cava.

Embryology: The right auricle is the persistent muscular wall of the primitive atrium.

Surrounding structures: Superior vena cava and arch of aorta (superior), Right Ventricle (inferior), right coronary artery (deep)

Trabeculae Carnae (of RV)

Muscular folds on the thick interior walls of the ventricle. These muscles are responsible for contracting the ventricle during systole.

May be confused with: Anterior papillary muscles, interventricular septum. The trabeculae carnae lie along the anterior wall and do not include the muscular projections (papillary muscles).

Septomarginal Trabeculae (Moderator Band)

The moderator band is a particularly prominent interior elevation of the right ventricle that contains specialized myocytes, part of the heart's conduction system. It carries part of the right bundle branch of the AV bundle to the anterior papillary muscle.

May be confused with: Anterior papillary muscles. Although both of these structures are elevations of the ventricular wall, the moderator band extends from the base of the anterior papillary muscle to the ventricular septum.

This muscle is a conical projection of the ventricular musculature attached to the cusp of the AV valve by way of a chordae tendinae. Together with the posterior and septal papillary muscles, it functions to close the AV (tricuspid) valve, preventing regurgitation of blood into the right atrium during systole.

May be confused with: posterior and septal papillary muscles. The anterior papillary muscle is located along the anterior ventricular wall. It can be identified by locating the moderator band, a projection found at the anterior papillary muscle's base that extends to the interventricular septum.

Anterior Cusp (AV Valve)

The anterior cusp of the tricuspid valve works in conjuction with the septal and posterior cusps to close the valve during systole to prevent regurgitation of blood into the right atrium.

Surrounding Structures: The anterior cusp joins the anterior papillary muscles by means of the chordae tendinae.

May be confused with: Septal or posterior cusp of the tricuspid valve. The anterior cusp is located along the anterior wall of the right ventricle.

This muscle is a conical projection of the ventricular musculature attached to the cusp of the AV valve by way of a chordae tendinae. Together with the anterior and septal papillary muscles, it functions to close the AV (tricuspid) valve, preventing regurgitation of blood into the right atrium during systole.

May be confused with: anterior and septal papillary muscles. The posterior papillary muscle is located near the interventricular septum within the right ventricle and is the farthest papillary muscle from the anterior ventricular wall.

The posterior cusp of the tricuspid valve works in conjuction with the septal and anterior cusps to close the valve during systole to prevent regurgitation of blood into the right atrium.

Surrounding Structures: The posterior cusp joins the posterior papillary muscles by means of the chordae tendinae.

May be confused with: Septal or anterior cusp of the tricuspid valve. The posterior cusp is located along the posterior wall of the right ventricle.