The radiographic appearance of the tracheobronchial tree as an indicator of visceral situs

Abstract

To arrive at an accurate anatomic diagnosis in patients with complex cardiovascular malformations or abnormal position of the heart, the situs of the viscera, or more specifically, that of the atria, must be known. Since the situs of the atria always corresponds to that of the tracheobronchial tree, the latter is a very reliable indicator of visceral (atrial) situs. A chest roentgenogram taken in the anteroposterior or posteroanterior projection will show the anatomy of the air-filled trachea and main bronchi, thus indicating whether there is situs solitus, situs inversus or “situs ambiguus”. The latter term is introduced to indicate that in many patients with asplenia or polysplenia syndrome, the visceral situs cannot be determined because of symmetrical development of normally asymmetrical organs.