The variable nature of the mediastinal contour lines: CT/chest radiography correlation

Interfacing of the lung with the mediastinum produces a number of mediastinal lines including those due to the innominate veins, left subclavian artery, paratracheal stripe, both anterior and posterior junction lines, the azygo-esophageal recess, descending aorta and paraspinal lines. Displacement or absence of one or more of these lines may be due to an abnormality of mediastinal contour or may indicate a mediastinal mass, but can occur in normal subjects. Correlative findings between chest radiography and chest computed tomography in 50 normal subjects illustrate the variable nature of these lines.