All of these are responsible for preferential shunting of well oxygenated blood from fetal right atrium to left hea, EXCEPT?
More oxygenated blood travels along the medial aspect of IVC and less along lateral aspect, facilitating shunting to opposite sides of hea, that is, more oxygenated travels to left hea through foramen ovale and less oxygenated to right ventricle. This is also facilitated by configuration of interatrial septum called crista dividens. So all are correct except option d.
Upper interatrial septum
Crista dividens
Pattern of blood flow in IVC
Size difference of left and right atrium
Fetal circulation