ostium primum การใช้

• As the septum primum grows, the ostium primum progressively narrows.
• The ostium secundum provides communication between the atria after the ostium primum closes completely.
• Before the ostium primum is completely occluded, a second opening called the ostium secundum begins to form in the septum primum.
• The crescent shape prevents the complete closure of the atria allowing blood to be shunted from the right to the left atrium through the opening known as the ostium primum.