Lung Fields, Diaphragm and Bones
Other aspects to consider when interpreting a chest x-ray are:
Lung fields
Lung fields should have equal radiolucency. Compare both sides, at corresponding levels, for normal vascular markings and any abnormal shadowing.
Check specific areas which are commonly missed – apices, costophrenic and cardiophrenic angles, and behind the heart.
Diaphragm
Position
The right is usually higher than the left. Elevation of a hemi diaphragm may be due to loss of lung volume above, a mass below in the abdomen, or injury to the phrenic nerve causing paralysis.
Shape
Flattening suggests hyperinflation, humps are common normal variants.
Air
If there are gas shadows beneath the diaphragm – determine whether it is normal air in the lumen of the stomach or the bowel, or free air in the abdomen.
Bones
Ribs for fractures and metastases – rotating the film through 90o can make ribs appear much clearer and easier to trace.
Spine (though specific views should be obtained for proper assessment).
Upper limb girdle.
Learning bite
Check specific areas of the film in which abnormalities are commonly missed – the apices, costophrenic and cardiophrenic angles, and behind the heart.