Situs inversus, (rare plural: sitūs inversi) short form of the Latin “situs inversus viscerum”, is a term used to describe the inverted position of chest and abdominal organs. It is called situs inversus totalis when there is a total transposition of abdominal and thoracic viscera (mirror image of internal organs normal positioning). Normal positioning of the organs - as found in the majority of individuals is called situs solitus.
Situs inversus is usually associated with dextrocardia (true mirror image) with only 3-5% incidence of congenital heart disease, most commonly transposition of the great vessels. Of these patients, 80% have a right-sided aortic arch. Situs inversus with levocardia (which is much rarer: 0.00005%) congenital heart disease is found in 95% of patients 4.
Imaging features on chest radiograph to be evaluated are:
- location of heart apex
- location of aortic arch
- locations of stomach bubble and liver
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- 4. Oski's pediatrics. LWW. ISBN:0781738946. Read it at Google Books - Find it at Amazon