Notes
External Features of the Heart
Sections
Base of heart
Located posteriorly, widest part of heart
Apex of heart
Located inferiorly, narrowest part of heart, points towards left side of body
4 Chambers of the heart:
Left and Right Atria, superiorly
- Auricles are ear-like extensions of the atria; expand to accommodate blood flow
- Superior and inferior vena cavae return blood to right atrium
- Pulmonary veins return blood to left atrium
Left and Right Ventricles, inferiorly
- Anterior and posterior interventricular sulci separate right from left
- Aorta carries blood away from left ventricle
- Pulmonary trunk carries blood away from right ventricle
Coronary sulcus (aka, atrioventricular groove)
Groove between the atria and ventricles where coronary vessels travel.
Full-Length Text
Here we will learn the external features of the heart and how it attaches to the roots of the great vessels.
We'll begin with the anterior surface of the heart.
First, define right and left sides of the heart.
Then, outline the heart, which is roughly triangular in shape;
Indicate that, in anatomical position, its apex points slightly towards the left side of the body.
Internally, the heart is divided into four chambers, which we'll approximate on the external surface.
Show that the atria are situated superiorly.
Show that the ventricles are situated inferiorly.
Notice that the ventricles are larger than the atria, and that, in anatomical position, the heart is rotated so that the left ventricle is turned towards the left side of the body.
Draw the auricles, which are ear-like extensions of the atria; when necessary, these pouches can expand to accommodate blood flow.
Then, inferior to the auricles, draw the visible portions of the coronary sulcus (aka, atrioventricular groove); coronary vessels travel within this groove.
Then, draw the anterior interventricular sulcus between the right and left ventricles.
Next, we'll show how the great vessels attach to the heart (blood flow through these vessels is addressed in detail in other tutorials).
On the superior aspect of the heart, show that the pulmonary trunk arises near the left auricle.
Then, show that the pulmonary trunk splits to form the right and left pulmonary arteries. Indicate that these vessels carry blood away from the heart to the lungs.
Next, show that the aorta, which is the major systemic artery of the body, arises at an angle and wraps around the pulmonary trunk.
Label the ascending and arch of the aorta; then, show that the aorta travels inferiorly within the thoracic and abdominal cavities as the descending aorta.
Indicate that blood flows away from the heart and to the body via the aorta.
Then, draw the vena cavae, which lie posteriorly: show the superior vena cava draining into the superoposterior aspect of the right atria, and, the inferior vena cava draining into the inferoposterior aspect of the right atria.
Indicate that blood flows from the body to the heart through the vena cavae.
Lastly, show the paired pulmonary veins, which drain into the heart posteriorly; though not visible here, we'll soon see that they drain into the left atrium.
Indicate that blood is returned to the heart from the lungs via the pulmonary veins.
Now we'll draw the posterior surface of the heart:
First, outline the heart.
Define right and left sides.
Again, show that the atria are located superiorly, and the ventricles, inferiorly.
Label the base of the heart, which is its widest part; it primarily overlies the left atrium.
Between the atria and ventricles, draw the coronary sulcus.
Then, between the ventricles, draw the posterior interventricular sulcus.
Now we'll draw the roots of the great vessels.
First, show that the superior and inferior vena cavae drain into the right atrium.
Indicate that blood from the body is returned to the heart via these vessels.
Then, show that the pulmonary veins drain into the left atrium; indicate that blood is returned to the heart from the lungs via these vessels.
Superior to these veins, show that the pulmonary trunk arises and splits to form the pulmonary arteries.
Indicate that blood is carried away from the heart and to the lungs via the pulmonary arteries.
Lastly, show that the aorta arises anteriorly and wraps posteriorly around the pulmonary trunk; indicate that the aorta carries blood away from the heart and to the body.
Notice that the vena cavae and aorta, which are the primary branches of the systemic circulation, extend along the vertical axis of the body;
The pulmonary arteries and veins run more horizontally because they transport blood to and from the lungs, which are situated to the right and left sides of the heart.