Many of the mediastinal structures have intermediate levels of density, so it is difficult to discern them with radiography. However, structures that are adjacent to the radiolucent lungs (less dense) can be visualized due to the difference in density.
Identify the following:
2. aortic knob (the "edge" that corresponds to the portion of the aortic arch in contact with the lung)
Can you see where the trachea birfurcates? Answer