右侧可见开放心脏的房间隔卵圆孔附近有一小块房间隔缺损。房间隔并未使得这块缺损关闭，因此形成了一条从左到右的旁路。
In the region of the foramen ovale on the interatrial septum is a small atrial septal defect, as seen in this heart opened on the right side. Here the defect is not closed by the septum secundum, so a shunt exists across from left to right.