Free peritoneal air is difficult to assess in a single, supine, plain film study. However, in the study above, one can appreciate the air visualized on both sides of the left hemidiaphragm. [Courtesy of Dr. N. Jaffer]
Air both inside and outside of the bowel wall creates contrast effect enabling the visualization of both the inner and outer limits of the bowel wall. [Courtesy of Dr. N. Jaffer]
Cupola sign refers to peritoneal air that is superior to the left lobe of the liver, having the appearance of a long, flat hat, hence the term “cupola” meaning hat. [Courtesy of Dr. N. Jaffer
Crescent sign – Upright abdominal radiograph showing abnormal presence of air under the right hemidiaphragm (arrow; left image). LLD abdominal radiograph showing air over the liver (arrow; right image). [Courtesy of Dr. N. Jaffer]
The image demonstrates massive ascites where fluid is seen throughout the abdomen, displacing the bowel centrally and superiorly as it is less dense than the fluid. Arrow points to ascites located in lesser sac. [Courtesy of Dr. N. Jaffer]
