看英文，了解房间隔形成

有朋友问我胎儿房间隔结构，我画了如下示意图给他。

以下是英文原文：

In the developing heart, the atria initially communicate with each other by an opening between the free edge of the septum primum and the endocardial cushions, known as the primary interatrial foramen or ostium primum (interatrial foramen primum), below the free margin of the septum.

Primary interatrial foramen
Gray465.png
Interior of dorsal half of heart from a human embryo of about thirty days. (Ostium primum visible below septum primum, but not labeled.)
Details
Identifiers
Latin foramen primum
Code TE E5.11.1.5.2.1.1
Anatomical terminology
[edit on Wikidata]
Closing of ostium primum Edit

This opening is closed by the union of the septum primum with the septum intermedium, and as the ostium primum closes, the communication between the atria is preserved with the formation of an opening in the upper part of the septum primum; this opening is known as the ostium secundum as it is chronologically the second opening that occurs in the septum primum.

A second entity, the septum secundum, develops to the right of the septum primum and the opening between the upper and lower limbs of the septum secundum is known as the foramen ovale of the heart. The part of the septum primum that remains to the left of the septum secundum acts as a one-way flow valve due to the greater pressures in the right atrium compared to the left atrium. At birth, the neonate begins breathing and the associated decrease in pulmonary vascular resistance leads to a reversal of the pressure differential between the atria. The left atrium now has a greater pressure than the right, effectively closing the one-way flow valve formed by the two septa. The two septa fuse later in life, to complete the formation of the atrial septum.

Persistence of the ostium secundum is the most common atrial septal defect.[1] Additionally, in a subset of the population, the foramen ovale is not overtly patent but the two septa have not fused. In normal physiologic circumstances, the septum primum acts as a one-way valve preventing blood flow as described above; but, if pathologic conditions cause right atrial pressure to exceed left atrial pressure, blood may flow through the foramen ovale from right to left.

从上述英文可以知道：

1，胚胎第30天，在共同心房腔内的顶部正中线
处，向下生长出一隔膜组织，称为原发隔，此隔向房室管心内膜垫方向生长，纵向将共同心房腔分为左、右两部分，最后与心内膜垫融合，在隔的游离缘中间凹陷处与心内膜塾完全融合前留有一小孔，称为第一房间孔(原发孔）

2，原发隔的下缘与心内膜垫逐渐融合，最后封闭原发孔。如果此孔不能封闭，则形成原发孔型房间隔缺损，由于此孔靠近心内膜垫及房室辦，故原发孔型房间隔缺损易合并心内膜塾垫缺损

3，在原发孔封闭之前，在原发隔的上部出现局部组织溶解吸收出现多个小孔，并逐渐融合扩大形成一个较大的孔道，称为第二房间孔（继发孔）

4，此同时，在原发隔(第一房间隔）的右侧心房顶部又生长出一隔膜，称为第二房间隔(继发隔)，呈圆弧形逐渐向房室管方向生长，覆盖上部继发孔后，在其中下部留有一孔，称为卵圆孔，继发隔下缘亦与心内膜塑融合。

注意：原发隔在左边，继发隔在右边！很好记：元祖……原左！😀

以上图来源于维基百科全书。