Morphology/Structure
The pectinate muscles are found on the anterior surface of the right and left atrial walls and their corresponding auricles. They’re roughly parallel bars of muscle that run in an anterolateral direction.
Key Features/Anatomical Relations
In the right atrium only, a strip of muscle called the crista terminalis runs perpendicular to the rest of the pectinate muscles. Where the crista terminalis and the opening of the superior vena cava meet is the approximate location for the sinuatrial node.
Function
The pectinate muscles can stretch to increase surface area and thus atrial volume.
