How can you be certain that the mass is not in the anterior mediastinum from the frontal CXR only?
Show Answer
Using what is known as "cervico-thoracic sign", which states: as the anterior mediastinum ends at the level of the clavicles the upper border of an anterior mediastinal lesion cannot be visualised extending above the clavicles. Any lesions with a discernible upper border above that level must be located posteriorly in the chest, i.e. apical segments of upper lobes, pleura, or posterior mediastinum.