Situs solitus
trunk
.Situs solitus (Latin: "usual site") is the medical term referring to the normal position of thoracic and abdominal organs.
gall bladder and a trilobed lung as well as the inferior vena cava, while left-sided organs are the stomach, single spleen, a bilobed lung, and the aorta.[1]
Variants on the normal picture are relatively uncommon. Complete reversal of all organs is known as situs inversus, while reversal of some organs but not others is called situs ambiguus or heterotaxy. Isolated reversal of the heart with normally-patterned viscera otherwise is termed dextrocardia.
Development
Although much of humans' external anatomy is
nodal cilia that move only in a counter-clockwise orientation, thus potentially producing a sort of 'current' in the embryo that would asymmetrically distribute these molecules.[1][3]