Juan F. Araùz
July 16, 2010
What isSitus 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 normalarrangement 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 Latin phrase meaning"inverted position of the internal organs."
Dextrocardia (the heart being located on the right side of the thorax) was first seen and drew by Leonardo da Vinci in 1452–1519, thenrecognised 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 populationsbut is less than 1 in 10,000 people.
Effect on anatomy
The condition affects all major structures within the thorax and abdomen. Generally, the organs are simply transposed through the sagittalplane. The heart is located on the right side of the thorax, the stomach and spleen on the right side of the abdomen and the liver and gall bladder on the left side. The left lung is trilobed and theright lung bilobed, and blood vessels, nerves, lymphatics and the intestines are also transposed.
But the main effect on the anatomy is the risks that bring the situs inversus when the person needsto be operated.
Totalis and Incompletus
If the heart is swapped to the right side of the thorax, it is known as situs inversus with dextrocardia or situs inversus totalis. If the heart remains inthe normal left side of the thorax, a much rarer condition (1 in 22,000 of the general population), it is known as situs inversus with levocardia or situs inversus incompletus. Situs inversus with...