Bronchial anatomy in right and left atrial isomerism (heterotaxy)

Bronchial anatomy with anterior views of trachea and bronchi. Arrows point to upper lobe bronchi.
(A) Normal bronchial situs with asymmetrical main bronchi with a right short bronchus to a trilobar right lung and a longer main bronchus to a left bilobar lung.
(B) Right atrial isomerism with symmetrical bilateral short main bronchi to bilateral trilobar lungs.
(C) Left atrial isomerism with symmetrical bilateral long main bronchi to bilateral bilobar lungs.