2. Chest radiograph — lateral projection

In this view the tracheal lumen appears as an almost vertical radiolucent band which ends just behind the superior aspect of the posterior border of the cardiac shadow. The radiodensities of the two hila are superimposed at the inferior end of the trachea.

The radiolucent area bounded by the sternum anteriorly and the cardiac shadow and ascending aorta posteriorly is called the retrosternal area. The radiolucent area directly posterior to the lower part of the cardiac shadow is called the retrocardiac area.

As in the PA projection, the diaphragm images as two separate hemidiaphragms in the lateral projection.