What is median arcuate ligament syndrome?

Median arcuate ligament syndrome (MALS) is a condition in which the median arcuate ligament presses too tightly on the celiac artery (a major branch of the aorta that delivers blood to the stomach, liver, and other organs) and the nerves in the area (celiac plexus).

Ligaments are bands of tissue that connect one bone or cartilage to another. The median arcuate ligament is shaped like an arch and goes around the aorta (the artery in the heart that carries blood throughout the body) to connect the diaphragm to the spine.

In a patient with MALS, the median arcuate ligament essentially acts like a hammer and the celiac axis acts like an anvil, compressing (squeezing) the nerves in between. This causes a number of symptoms, such as pain in the abdomen that can be made worse by eating or activity.

It is important to differentiate median arcuate ligament syndrome (MALS) from median arcuate ligament compression. Median arcuate ligament compression occurs in about 10-25% of the population and does not cause any symptoms. In a very small number of these individuals, MALS is present, and patients will have the symptoms listed below.

MALS occurs most often in thin, younger women. It is a very rare condition.

What are the signs and symptoms of median arcuate ligament syndrome?

The first sign of MALS is pain in the upper abdomen after eating. The pain causes patients to avoid eating, which can lead to weight loss (often more than 20 pounds).Other associated symptoms may include:

  • Nausea
  • Diarrhea
  • Vomiting
  • Delayed gastric emptying (a delay in food moving from the stomach into the small intestine)

What causes median arcuate ligament syndrome?

It is believed that MALS is caused by the median arcuate ligament compressing, or pinching the celiac plexus nerves over the celiac artery. The squeezing of these nerves can cause a pain similar to the pain patients with carpal tunnel syndrome feel in their hands. Another cause may be the lack of blood flow to the organs supplied by the celiac artery, though this theory is controversial.

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