Concept of situs
Situs refers to the “sidedness” of the body. A normal situs, situs solitus, indicates that right-sided structures are found on the right side of the body, and left-sided structures are found on the left side of the body. In situs inversus, there is an abnormal mirror image appearance, with left-sided structures found on the right side of the body and vice versa. Situs ambiguous refers to heterotaxy syndromes in which visceral and thoracic organs are ambiguously mixed in their positions, usually with bilateral right-sidedness (asplenia) or bilateral left-sidedness (polysplenia). Heterotaxy syndromes usually include cardiac malformations, gut rotational abnormalities (malrotation), and vascular abnormalities.
