Discover the possible root causes of pain in the abdomen and also find out when you must see a doctor. Because they include the bladder, kidney, and ureter), ordinary X-rays of the abdomen also are referred to as a KUB (. When there is digestive tract obstruction, the KUB may show enlarged loopholes of intestines filled with copious quantities of fluid as well as air. People with a perforated abscess might have air escape from the stomach right into the stomach dental caries.