What is the approach to evaluating a conventional abdominal radiograph?

Bones: Evaluate the integrity of the bones.
Stones: Check for calcifications or foreign bodies.
Gases: Check for extraluminal gas—for example, subdiaphragmatic (free air), between the bowel loops, or in the bowel wall (pneumatosis)—and intraluminal gas (dilatation of the bowel, thickness of the wall, air-fluid levels, and displacement of loops). Check for peritoneal fluid between the flank stripe and adjacent bowel gas.
Masses: Check the normal viscera (i.e., the liver, spleen, bladder, and flank) and note any abnormal masses.