Dalgleish A E
J Morphol. 1976 Jul;149(3):369-82. doi: 10.1002/jmor.1051490306.
The septum primum in the mouse originates as a thickened primordium with a straight rather than a sickle-shaped ventral border. It is covered on its ventral border by anterior cushion material which is continuous over the roof of the atrium with the principal anterior cushion mass. A process of cavitation thins the septum primum and precedes actual fenestration. This process shifts the membranous septum to the left thereby providing room for the septum secundum to overlap on the right side. The septum primum cannot contact the posterior cushion until closure of the sinus venosus gutter which is described. The closure of the interatrial foramen, later the foramen primum, is accomplished by cell growth of the anterior cushion material. The ventral thick border of the septum primum contributes to the ventral limbus and the caudal thickened boundary of the fossa ovalis with some contribution from the left venous valve. These boundaries as well as the membranous portion of the interatrial septum are derived from the same primordium, namely the septum primum.
小鼠的原发隔起源于一个增厚的原基，其腹侧边缘是直的，而非镰刀状。其腹侧边缘被前垫组织覆盖，该组织在心房顶部与主要的前垫团块相连。空泡形成过程使原发隔变薄，并先于实际的开窗。这一过程将膜性隔向左移位，从而为继发隔在右侧重叠提供空间。在上述静脉窦沟关闭之前，原发隔无法接触后垫。房间孔（即第一孔）的关闭是通过前垫组织的细胞生长实现的。原发隔的腹侧厚边缘对腹侧缘以及卵圆窝的尾侧增厚边界有贡献，左静脉瓣也有一定贡献。这些边界以及房间隔的膜性部分都源自同一个原基，即原发隔。
