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. The normal arrangement is known as situs solitus. In other rare cases, in a condition known as situs ambiguus or heterotaxy, situs cannot be determined.

The term situs inversus is a short form of the Latin phrase "situs inversus viscerum", meaning "inverted position of the internal organs". Dextrocardia (the heart being located on the right side of the thorax) was first seen and drawn by Leonardo da Vinci in 1452–1519, and then recognised by Marco Aurelio Severino in 1643. However, situs inversus was first described more than a century later by Matthew Baillie.

The prevalence of situs inversus varies among different populations but is less than 1 in 10,000 people.