Sandbox: Ifeoma

Embryology

• At about week 4 of pregnancy, the septum primum and septum secundum forms to divide the primordial single atrium into right and left.
• The crescent-shaped septum primum grows from primordial atrial roof towards the endocardial cushion. This partially divides the common atrium into left and right halves.
• The formation of the endocardial cushions occurs on the ventral and dorsal walls of the atrioventricular canal. The fusion divides the atrioventricular canal into right and left sides.