Heterotaxia , also called the indeterminate position of the internal organs or situs ambiguus, is a rare congenital anomaly when the location of the main internal organs differs from both their normal position (situs solitus) and their complete mirror image (situs inversus).
In contrast to the normal position of internal organs and transposition of internal organs, heterotaxia is usually associated with complex functional potentially fatal disorders.
Anatomical structure
Since heterotaxia includes the entire spectrum of possible mutual arrangements of internal organs and violation of their symmetry, there is no single description of all cases. For ease of diagnosis, all cases are usually divided into two groups:
Bilateral left-sidedness (also called left isomerism, heterotaxia with polysplenia) which is characterized by:
- short horizontal bronchi;
- both lungs have two lobes;
- two left atria;
- midline position of the liver;
- numerous spleens (polyspleniya);
- interrupted inferior vena cava.
Bilateral right-sidedness (also called right isomerism, heterotaxy with asplenia) for which the following are characteristic:
- long vertical bronchi;
- both lungs have three lobes;
- two right atria;
- midline position of the liver;
- lack of spleen (asplenia).