Celiac artery compression syndrome (CACS), also known as median arcuate ligament syndrome (MALS), celiac axis syndrome, or Dunbar syndrome, is defined as compression of the celiac artery and celiac plexus by the median arcuate ligament. Compression of the artery impairs blood flow to the digestive tract, causing ischemia and resulting symptoms. Irritation and compression of the celiac plexus also contribute to symptoms. This is characterized by postprandial epigastric pain, unintentional weight loss, and an abdominal bruit. The abdominal bruit may be moderate to loud and prominent in the upper left quadrant, but it is not always present. Other symptoms include nausea, vomiting, diarrhea, bloating, and exercise intolerance. Given the vague nature of complaints, clinicians must have a high index of suspicion. CACS may be a diagnosis of exclusion after extensive evaluation. Symptoms are often chronic and usually lead to invasive testing.

This syndrome is more prevalent in women compared with men (4:1 ratio), and patients tend to have a thin body habitus. CACS usually presents in middle-aged adults, but it can occur in children and adolescents. It can also be associated with rapid, often intentional, weight loss in adults. About 7% of patients will be asymptomatic.