Chilaiditi syndrome is a rare condition which occurs when there is a loop of large intestine (usually transverse colon) in between the diaphragm and the liver, visible on plain abdominal X-ray or chest X-ray.
Normally this causes no symptoms, and this is called Chilaiditi's sign. The sign can be permanently present, or sporadically. This anatomical variant is sometimes mistaken for the more serious condition of having air under the diaphragm (pneumoperitoneum) which is usually an indication of bowel perforation. This may lead to unnecessary surgical interventions.
Absence or laxity of the ligament suspending the transverse colon or of the falciform ligament are also thought to contribute to the condition. It can also be associated with relative atrophy of the medial segment of the left lobe of the liver. In this case, the gallbladder position is often anomalous as well - it is often located anterior to the liver, rather than posterior.