Cavity of atrium: anatomy, location and function

What it is

The cavity of the atrium is the blood-filled chamber of the right or left atrium.

Location

The right atrium receives the superior and inferior venae cavae and the coronary sinus and opens through the tricuspid valve into the right ventricle. The left atrium receives four pulmonary veins and opens through the mitral valve into the left ventricle.

Function

The atria receive blood returning to the heart and pass it into the ventricles.

Body system

Cardiovascular · paired (left and right)

FMA ID

FMA11359 (Foundational Model of Anatomy)

Key facts

• The right atrium has a rough anterior wall with pectinate muscles and a smooth posterior part; the left atrium wall is mostly smooth.
• The right atrium receives deoxygenated blood from the venae cavae and coronary sinus; the left atrium receives oxygenated blood from four pulmonary veins.
• The two atria are separated by the interatrial septum, which bears the fossa ovalis on its right side.

The nearest named structures in the 3D model, measured from the centre of each part:

• Wall of atrium · cardiovascular
• Esophagus · digestive
• Posterior cusp of aortic valve · cardiovascular
• Main bronchus proper · respiratory
• Anterior cusp of aortic valve · cardiovascular
• Accessory hemiazygos vein · cardiovascular
• Anterior leaflet of mitral valve · cardiovascular
• Septal leaflet of tricuspid valve · cardiovascular
• Coronary sinus · cardiovascular
• Great cardiac vein · cardiovascular