Closure of the foramen primum results from fusion of which of the following structures?
Septum secundum and the fused atrioventricular cushions
Septum secundum and the septum primum
Septum primum and the fused atrioventricular cushions
Septum primum and the septum spurium
C. The foramen primum forms between the free edge of the septum primum and the atrioventricular (AV) cushions. It is closed when the septum primum fuses with the AV cushions.
CVS Embryology