CT Scans of a patient with Situs inversus.
In situs inversus, the organs are reversed/mirrored in their alignment compared to the usual organ composition. This is actually called heterotaxy. Heterotaxy is a rare congenital defect in which the major visceral organs are distributed abnormally within the chest and abdomen. Here you can see that the heart, instead of normally forming on the left side of the chest, is located on the right side. Also the liver is on the left side, causing in the left kidney being placed lower than the right (usually it is the other way round). Heterotaxy has been known to affect the development of the heart, liver, lungs, intestines, and spleen. Babies with Heterotaxy syndrome are usually first identified because they have structural problems with their hearts or livers. For every 1,000,000 babies born, 4 of them will have Heterotaxy syndrome. The exact cause of Heterotaxy is not known, but the symptoms result from the way that the internal organs turn into position during fetal development. This rotation can be affected by many different factors including infection, genetics, or exposures to certain chemicals. There are a few reports of families having several members with Heterotaxy, but the exact cause has not been identified yet.
