What are the causes of situs inversus?

Congenital: This rearrangement of the organs happens during the fetal satge of development. Cause is unknown.

Situs inversus: Situs inversus (also called situs transversus or oppositus) is a congenital condition in which the major visceral organs are reversed or mirrored from their normal positions. A example of situs inversus is seen in the x-ray, where the heart is not in its normal position, it is reveresed. Many people with situs inversus totalis are unaware of their unusual anatomy until they seek medical attention.

Not sure: No known cause. It occurs in utero can be associated with some syndromes.