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Health condition

Median arcuate ligament syndrome, a rare and contested cause of pain after eating.

A diagnosis of exclusion - reached only once the usual gut causes have been ruled out, and confirmed by imaging and a diagnostic nerve block before surgery is ever considered.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Editorial team

    Written by our editorial team from the UK sources listed on each page.

  • 02

    Sourced from guidance

    Checked against vascular society guidance and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern practice, including duplex-first assessment, coeliac plexus blocks and laparoscopic release.

Key facts

MALS at a glance.

The essentials, in plain English - what it is, why the diagnosis is contested, and how it’s assessed and treated in the UK today.

  • What it is

    Compression of the coeliac artery and coeliac plexus by the median arcuate ligament, a fibrous band of the diaphragm - also called coeliac artery compression syndrome or Dunbar syndrome.

  • Who it affects

    More common in young, thin women - though the anatomical compression itself is seen incidentally in many people without symptoms.

  • A controversial diagnosis

    Considerable overlap with functional gut disorders - this is a diagnosis of exclusion, made only after other causes are ruled out.

  • Classic pattern

    Postprandial epigastric pain - worse after eating - with nausea, food fear and weight loss in more established cases.

  • First-line imaging

    Duplex ultrasound measuring coeliac artery velocity on expiration, followed by CT or MR angiography for the characteristic hook deformity.

  • Definitive treatment

    Laparoscopic median arcuate ligament release - reserved for cases with a clear match between symptoms, imaging and a positive coeliac plexus block.

Why this guide matters

Exclusion first, surgery last.

MALS is rare, genuinely useful to diagnose correctly, and easy to over-diagnose. The three points below shape everything else on this page.

  • It is a diagnosis of exclusion

    Gastroscopy, colonoscopy, gastric emptying studies and coeliac screening come first - MALS is only considered once these are clear.

  • Imaging alone is not enough

    Many people have coeliac artery compression on a scan with no symptoms at all - imaging must match the clinical picture, not stand alone.

  • A block predicts surgical success

    A coeliac plexus block gives real prognostic information - relief after the block is one of the best predictors of how surgery will go.

How the diagnosis is made

From chronic pain to a confirmed diagnosis.

The steps a specialist commissioned vascular and gastroenterology team will normally follow, in order - so you know what to expect and why.

  1. 01

    Excluding

    Full history and examination

    Chronic postprandial epigastric pain, food avoidance and weight loss - sometimes an abdominal bruit heard on expiration.

  2. 02

    Excluding

    Exclude other GI causes first

    Gastroscopy, colonoscopy, gastric emptying studies and coeliac disease screening before MALS is even considered - see dyspepsia and IBS for the differential context.

  3. 03

    Excluding

    Exclude psychiatric and functional causes

    Chronic abdominal pain has many drivers - functional GI disorders and psychological factors must be assessed alongside the vascular picture.

  4. 04

    Confirming

    Duplex ultrasound

    First-line vascular imaging - a dynamic study measuring coeliac artery velocity, which rises further on expiration when the ligament compresses the vessel.

  5. 05

    Confirming

    CT or MR angiography

    Demonstrates the characteristic hook or J-shaped deformity of the coeliac artery from external compression, best seen on expiratory imaging.

  6. 06

    Confirming

    Coeliac plexus block

    A diagnostic and prognostic test - specialist commissioned pain medicine or interventional radiology. Symptom relief after the block predicts how well surgery is likely to work.

  7. 07

    Deciding

    Specialist commissioned MDT

    Vascular surgery, gastroenterology and pain medicine review the full picture together before any decision on surgery, given how complex and contested this diagnosis can be.

Typical timeline: months of exclusion work before a confident diagnosis - by design, not delay.

Symptoms

What MALS actually feels like.

A pattern of pain that follows meals, plus the features that mean it’s time to be seen urgently.

  • Postprandial epigastric pain

    Pain in the upper abdomen that reliably worsens after eating - often the dominant and most consistent feature.

  • Food avoidance and weight loss

    Fear of triggering pain leads many people to eat smaller amounts or skip meals, sometimes causing significant weight loss.

  • Nausea

    Often accompanies the postprandial pain, though vomiting is less consistent than in other GI conditions.

  • Abdominal bruit

    An audible vascular sound on examination, classically heard on expiration as the ligament compresses the artery further.

  • Exercise-related worsening

    Some people notice symptoms flare with exertion or particular postures, reflecting the dynamic nature of the compression.

  • Positional variation

    Symptoms can shift with posture and breathing, since the degree of compression changes with diaphragmatic movement.

  • Chronic course

    Symptoms are typically present for months to years before a diagnosis is reached, reflecting how much needs to be excluded first.

  • Red flag - unexplained weight loss

    Significant, unexplained weight loss alongside postprandial pain deserves thorough and urgent GI and vascular assessment.

Treatment

How MALS is treated in the UK.

Conservative measures and diagnostic blocks first, laparoscopic release for confirmed cases with a clear symptom-imaging-block correlation.

  • Dietary modification

    Small, frequent meals reduce the postprandial demand on the coeliac circulation - a reasonable first step for mild or uncertain cases.

  • Pain management

    Structured pain-medicine input while investigations continue, particularly important given the chronic pain burden many people carry by diagnosis.

  • Coeliac plexus block

    Specialist commissioned pain medicine or interventional radiology - provides diagnostic clarity and can give temporary symptom relief in its own right.

  • Laparoscopic median arcuate ligament release

    Specialist commissioned vascular or upper GI surgery - the definitive treatment, dividing the ligament to decompress the coeliac artery in confirmed, well-selected cases.

  • Angioplasty or stenting

    Specialist commissioned interventional radiology - selective use for residual coeliac artery narrowing, sometimes combined with surgical release.

  • Psychological support

    Specialist psychology input given the diagnostic uncertainty and chronic pain involved - functional overlay is common and deserves compassionate attention.

  • Careful patient selection

    Specialist commissioned MDT - outcomes are consistently best when symptoms, imaging and a positive coeliac plexus block all point the same way.

  • Specialist commissioned MDT review

    Vascular surgery, gastroenterology, pain medicine and psychology working together, reflecting the genuine diagnostic complexity of MALS.

What this guide is based on

The sources behind every claim on this page.

Vascular society guidance and specialist literature, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, gastroenterologist or vascular surgeon knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • Society for Vascular Surgery. Clinical practice guidelines on visceral artery compression syndromes.

  • Vascular Society of Great Britain and Ireland. Guidance on median arcuate ligament syndrome assessment.

  • European Society for Vascular Surgery. Guidelines on the diagnosis and management of mesenteric artery disease.

  • Peer-reviewed surgical literature on laparoscopic median arcuate ligament release outcomes.

Red flags

When chronic abdominal pain needs urgent attention.

Most chronic postprandial pain is not MALS. These are the situations where the priority shifts, and a specialist opinion is needed sooner.

  • Significant unexplained weight loss

    A strong indicator that needs thorough GI and vascular work-up rather than being assumed to be MALS from the outset.

  • Signs of bowel ischaemia

    Severe, unrelenting abdominal pain with systemic illness needs emergency assessment to exclude acute mesenteric ischaemia.

  • Uninvestigated dyspepsia over 55

    New upper GI symptoms in this age group warrant gastroscopy to exclude malignancy before any vascular work-up begins.

  • Rectal bleeding or anaemia

    Should prompt colonoscopy and standard GI investigation rather than being attributed to coeliac artery compression.

  • Suspected other visceral artery disease

    Multi-vessel compression or atherosclerotic disease affecting the superior mesenteric artery needs broader vascular assessment - see mesenteric ischaemia.

  • Persistent symptoms after surgery

    A minority do not improve after ligament release - this needs prompt specialist review rather than repeat surgery being assumed the answer.

  • Severe psychological distress

    Chronic, unexplained pain carries a real mental-health burden - low mood or hopelessness deserves urgent support alongside physical investigation.

  • Coexisting lower limb ischaemia

    Widespread vascular disease affecting other territories should prompt a broader vascular work-up rather than a single-vessel focus.

  • Diagnostic uncertainty persisting

    When symptoms, imaging and block results do not agree, that mismatch is itself a signal to slow down rather than proceed to surgery.

Living with it

A rare diagnosis, handled with care.

Four things that make the biggest difference while a diagnosis is being reached, and afterwards - simple dietary changes, honest tracking, early support and a considered approach to surgery.

A quiet reminder

Patience with the process protects the outcome.

A careful work-up that rules things out properly gives surgery, if it happens, the best chance of actually helping.

  1. 01 Eat

    Smaller, more frequent meals

    Reducing the postprandial demand on the coeliac circulation can meaningfully ease day-to-day symptoms while investigations continue.

  2. 02 Track

    Keep a symptom and food diary

    A clear record of what triggers pain helps the MDT judge how well any one intervention, including a coeliac plexus block, is actually working.

  3. 03 Support

    Ask about psychological support early

    Given how long this diagnosis can take to reach, chronic pain support and psychology input are worth arranging well before any surgical decision.

  4. 04 Decide

    Weigh surgery on correlation, not hope

    The best outcomes follow clear agreement between symptoms, imaging and block response - a cautious, well-selected decision beats a rushed one.

Frequently asked

Everything we get asked about MALS.

Quick answers on diagnosis, coeliac plexus blocks, and when surgery is the right call.

  • What is median arcuate ligament syndrome?

    A rare vascular compression disorder in which the median arcuate ligament, part of the diaphragm, compresses the coeliac artery and the coeliac plexus of nerves. This can cause chronic postprandial abdominal pain, though the diagnosis is complex and controversial because many people have the anatomical compression without symptoms.

  • Why is MALS considered a controversial diagnosis?

    There is considerable overlap between MALS and functional gastrointestinal disorders such as dyspepsia and irritable bowel syndrome. Coeliac artery compression is also seen incidentally on scans in people with no symptoms at all, so it is treated strictly as a diagnosis of exclusion.

  • What tests are used to diagnose MALS?

    Gastroscopy, colonoscopy, gastric emptying studies and coeliac disease screening come first to exclude other causes. Duplex ultrasound measuring coeliac artery velocity on expiration is the first-line vascular test, followed by CT or MR angiography to look for the characteristic hook-shaped deformity of the artery.

  • What does a coeliac plexus block involve?

    It is an injection, performed by specialist commissioned pain medicine or interventional radiology, that numbs the coeliac plexus of nerves. Symptom relief after the block is both diagnostic and prognostic - it helps predict how well a patient is likely to respond to surgical release.

  • What is laparoscopic median arcuate ligament release?

    A specialist commissioned surgical procedure, usually performed by vascular or upper GI surgeons, that divides the ligament to decompress the coeliac artery. It is the definitive treatment, reserved for cases where symptoms, imaging and a positive coeliac plexus block all correlate closely.

  • Does surgery always work?

    Not always. Outcomes are best when there is clear correlation between symptoms, imaging findings and block response, which is why careful patient selection by a specialist commissioned MDT is so important. Some people need additional angioplasty or stenting if narrowing persists after ligament release.

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