What Is Median Arcuate Ligament Syndrome (MALS)?

Medically Reviewed by Minesh Khatri, MD on September 10, 2023
4 min read

If you have belly pain and you've lost some weight lately, one possible reason is a condition called MALS. The full name of this rare problem: median arcuate ligament syndrome.

The median arcuate ligament is a band of tissue shaped like an arc in the lower part of your chest. It passes over the aorta -- a blood vessel that carries blood from the heart.

When you have MALS, this ligament sits lower than usual and presses on the celiac artery. This blood vessel delivers blood to the stomach, liver, and other organs in your belly.

It's the pressure from the ligament that causes trouble. It may slow blood flow to the organs in your belly and press on nerves around the artery. Both can cause pain.

Some people who have MALS never feel any symptoms. When symptoms do show up, it’s most often in women ages 20 to 40. But men, older adults, and children can get this condition, too.

The main symptom you'll notice with MALS is pain in your upper belly. It may hurt more after you eat or work out. The pain might make it hard to eat, which can cause you to lose weight.

If you have MALS, you might also have:

If you have pain in your belly, especially if you've lost weight, have your doctor check it out. Gallbladder trouble, liver disease, and digestive system conditions can also cause these kinds of symptoms. Belly pain along with chest pain or palpitations could be a problem with your heart.

MALS can be hard to diagnose because its symptoms are like those of so many other conditions. Your doctor will try to rule out diseases like:

Your doctor will go over your medical history and symptoms and do an exam. When they put a stethoscope on your belly, they may hear a whooshing sound called a bruit. It's a sign of a problem with the blood flow through an artery.

You may have blood and urine tests to rule out other diseases and other blood tests to diagnose MALS.

X-rays, ultrasound, and an upper endoscopy -- a test that uses a lighted scope to look inside your digestive tract -- help doctors find problems with your digestive tract. During an endoscopy, the doctor may remove a small piece of tissue for testing.

If your doctor can't find the source of the problem, you might have another kind of ultrasound called a mesenteric duplex ultrasound. This test checks blood flow through the blood vessels in your belly.

A CT angiography or magnetic resonance angiogram (MRA) can confirm that there is pressure on your celiac artery. CT angiography uses X-rays and a computer to make detailed pictures of your organs and tissues. MRA shows the inside of your blood vessels.

The main treatment for MALS is surgery to release the pressure that the median arcuate ligament puts on your artery. Your surgeon may also remove some pinched nerves. Your pain should go away right after surgery, but it could take up to 4 weeks to get relief.

If you don't want surgery or you can't have it, your doctor can give you a shot called a celiac plexus block to relieve the pain. First, you'll get medicine through a vein (IV) to relax you. As you lie on your belly, your doctor will numb your back and insert two thin needles. Using an X-ray as a guide, the doctor will inject a pain medicine or a steroid into your back.

It can take between two and 10 shots to ease the pain from MALS. Sometimes a celiac plexus block can keep pain under control for months or years.

Surgery improves pain in up to 80% of people. In a small percentage of people, scar tissue builds up after surgery and narrows the celiac artery. Usually the scar tissue doesn't cause pain. If it does, another procedure can open the artery and get blood flowing again.

If you have a celiac plexus block, you may need repeat shots to keep your pain at bay.