Embryologically, the left atrium also consists of sinus enosus and primitie auricle, and they form the same anatomical components as in the right atrium.

• 而具有粗糙小梁内面的原始心房则发育成了心耳。心房的静脉部在心房后部与上下腔静脉衔接，下部的冠状窦与房间隔相连。