What is the meaning of situs solitus?

From the Guidelines

Situs solitus refers to the normal arrangement of organs in the body, where the heart is positioned on the left side of the chest with its apex pointing to the left, and is found in approximately 95% of cases of congenitally corrected transposition of the great arteries (CCTGA) [ 1 ]. This normal arrangement is crucial for medical diagnosis and treatment, particularly in cases of congenital heart defects. Some key features of situs solitus include:

• The heart is positioned on the left side of the chest with its apex pointing to the left
• The liver is on the right side of the abdomen
• The stomach and spleen are on the left side In the context of CCTGA, situs solitus is significant because it affects the positioning of the coronary arteries and ventricles, with the morphological right ventricle being supplied by a right coronary artery [ 1 ]. Understanding situs solitus is essential for:
• Medical imaging interpretation
• Surgical planning
• Diagnosing certain genetic disorders that may affect organ positioning It is worth noting that situs solitus is the standard anatomical configuration found in most people, and any deviation from this arrangement can have significant implications for health and treatment [ 1 ].

From the Research

Definition of Situs Solitus

• Situs solitus refers to the normal arrangement of internal organs in the body, with the left atrium, spleen, stomach, and trilobed lung on the left side, and the liver and bilobed lung on the right side 2
• It is derived from Latin, meaning "normal" or "usual" 2
• Situs solitus is considered the normal or expected arrangement of visceral organs, as opposed to situs inversus (mirror-image reversal) or situs ambiguus (abnormal arrangement) 3, 4

Characteristics of Situs Solitus

• Individuals with situs solitus do not typically experience fatal dysfunction of their organ systems, as the general anatomy and morphology of the abdominothoracic organ-vessel systems are conserved 2
• Situs solitus is associated with a low incidence of congenital heart disease, less than 1% 4
• It is the normal position of the cardiac atria and viscera, with levocardia (left-sided heart) being the typical presentation 4

Distinction from Other Situs Types

• Situs solitus is distinct from situs inversus, which is a mirror-image reversal of the internal organs 2, 4, 5
• It is also distinct from situs ambiguus, which refers to an abnormal arrangement of internal organs that does not fit the typical pattern of situs solitus or situs inversus 2, 3, 4