Laterality Flashcards
What is situs solitus?
The normal anatomical position of the heart and abdominal viscera.
Cardiac apex, spleen, stomach and aorta on the left.
Liver and inferior vena cava on the right. Fulcher and Turner (2002).
What is situs inversus?
Mirror image location of the viscera relative to situs solitus.
Fulcher and Turner (2002).
What is situs inversus with dextrocardia?
How many people with this have congenital heart disease?
Mirror image location of the heart and viscera relative to situs solitus. Cardiac apex, spleen, stomach and aorta on the right and the liver and IVC on the left.
Congenital heart disease in 3-5% of patients. Tonkin, I.L. (1984).
What is situs inversus with levocardia?
Mirror image of the viscera relative to situs solitus, only with a left-sided cardiac apex.
Nearly all affected individuals have congenital heart disease. Tonkin I.L. (1984).
What is situs ambiguus (heterotaxia)?
Abnormal arrangement of organs and vessels as opposed to the orderly arrangement of situs solitus or situs inversus.
50-100% have congenital heart disease.
Fulcher and Turner (2002).
What is situs ambiguus with polysplenia?
Often left isomerism.
Midline or ambiguous locations of the majority of the abdominal organs and multiple spleens. 50-90% have congenital heart disease.
Fulcher and Turner (2002).
What is situs ambiguus with asplenia?
Often right isomerism.
Midline or ambiguous locations of the majority of the abdominal organs and absence of spleen. 99-100% have congenital heart disease.
Fulcher and Turner (2002).
Left Isomerism
Heart has 2 long, narrow atrial appendages, both lungs are bilobed with long, hyper arterial bronchi.
Fulcher and Turner (2002).
Right Isomerism
Heart has 2 pyramidal atrial appendages, both lungs are trilobed with short eparterial bronchi.
Fulcher and Turner (2002).
Clinical implications of laterality disorders.
Example - Situs inversus totalis.
No symptoms, but it alters the positions of organs producing odd symptoms during the disease process.
Laterality disorders require alteration to routine procedures.
24-41% undiagnosed, up to 30% misdiagnosed and up to 12% seen again by a surgeon.
Nelson et al. (2001).
Situs inversus and lymphoma
Multiple enlarged nodes around the aorta.
IVC on the left.
Multiple enlarged retroperitoneal lymph nodes adjacent to the aorta and the IVC.
One particular large node to the right of the aorta mistaken for the IVC.
Causes problems for biopsies.
Fulcher and Turner (2002).
Pacemaker implantation
46 year old female with dextrocardia and situs inversus totalis.
Needed to place atrial and ventricular leads via the right subclavian vein into the right atrium and apex of the right ventricle.
Challenging due to extra angle placed on the leads to pass through abnormal course of SVC and reversed positions of right atrium and ventricle.
Invert image to simulate situs solitus positions.
Surgical issues with laterality disorders
Surgical instruments and techniques predominantly right handed.
Situs patient - right handed surgeon dissect with relatively unskilled left hand or cross instruments to use right hand.
Oms and Badia (2003).
