Which number on this diagram identifies the heart anatomy location of the septum?

To identify the location of the septum in the heart anatomy diagram, look for the number corresponding to the structure that separates the left and right sides of the heart. The septum is typically indicated as the muscular wall between the left and right atria (interatrial septum) and the left and right ventricles (interventricular septum). If you can provide the specific numbers from the diagram, I can help you determine which one refers to the septum.