becomes divided into right and left by a septum, the septum primum. The septum primum (from Latin 'first septum') grows downward into the single atrium...

right atrium to the left. As the septum primum grows, the ostium primum progressively narrows. Before the ostium primum is completely occluded, a second...

downward from the upper wall of the atrium immediately to the right of the septum primum and ostium secundum. It is important in the closure of the foramen ovale...

The Primum Mobile is the outermost moving sphere in the geocentric model of the universe in medieval and Renaissance astronomy. The septum primum is a...

interatrial foramen or ostium primum (or interatrial foramen primum). The foramen lies beneath the edge of septum primum and the endocardial cushions....

The opening between the bottom edge of the septum primum and endocardial cushions is the ostium primum (first opening). The extensions of the upper...

fusion of the septum primum and the septum secundum; in healthy hearts, this fusion form the fossa ovalis, a portion of the interatrial septum which corresponds...

primum except for a small opening below the septum, the ostium primum. As the septum primum grows, the ostium primum narrows and eventually closes. Before it...

septum primum, a precursor to the interatrial septum of the human heart. It is not the same as the foramen ovale, which is an opening in the septum secundum...

foramen, below the free margin of the septum. This opening is closed by the union of the septum primum with the septum intermedium, and the communication...