What anatomical structures are well seen with radiography  
 

Let's use the chest radiograph ("chest x-ray" or "CXR" ) on the right to examine how various tissues look on x-ray. The film is a frontal view of the chest.

Bones are quite dense and appear white. Look at the ribs and clavicles.

Air does not attenuate much of the x-ray beam. Structures that don't attenuate much of the beam appear black or "radiolucent". Since the lungs are composed primarily of air, they appear black on radiographs.

Soft tissues appear in varying shades of gray. They are not well seen unless there is a tissue next to them of very different composition. For example, on the CXR, the edges of the heart and mediastinum can be seen discretely from the lungs. However, one cannot differentiate internal structures of the heart or mediastinum, such as the aorta and pulmonary arteries, from each other. Because these tissues have similar densities, they attenuate the x-ray beam similarly and therefore look the same on x-rays.