<aside>

Median Arcuate Ligament Syndrome (MALS), also known as celiac artery compression syndrome, is a rare condition caused by external compression of the proximal celiac artery by the median arcuate ligament (MAL) — a fibrous band of the diaphragm — leading to chronic postprandial abdominal pain due to mesenteric ischemia or celiac plexus irritation.

</aside>

Pathophysiology

The median arcuate ligament is a fibrous arch formed by the diaphragmatic crura at the level of T12.
Normally lies superior to the celiac artery origin.
In MALS, it inserts lower than normal, compressing the celiac trunk, especially during expiration (as diaphragm ascends).

![(A) Normal median arcuate ligament (MAL) position; (B) lower MAL position: no significant celiac artery compression during inspiration; (C) lower MAL position: celiac artery compressed by the MAL during expiration.

Liu Y, Zheng H, Wang X, Wang Z, Zhu Q, Wen C and Tong Y (2023) Ultrasound characteristics of abdominal vascular compression syndromes. Front. Cardiovasc. Med. 10:1282597. doi: 10.3389/fcvm.2023.1282597](attachment:2a5844e5-919a-4012-ac17-a64c244b748d:fcvm-10-1282597-g001.webp)

(A) Normal median arcuate ligament (MAL) position; (B) lower MAL position: no significant celiac artery compression during inspiration; (C) lower MAL position: celiac artery compressed by the MAL during expiration.

Epidemiology

Feature	Details
Age	20–50 years
Sex	Female > Male (2–3:1)
Prevalence	Anatomical compression seen in ~10–24%, but symptomatic in <2%

Clinical Features

Mechanisms of symptoms:

Dynamic vascular compression → ↓ celiac artery blood flow
Neuropathic pain → from celiac ganglion irritation

Symptom	Comment
Postprandial epigastric pain	Crampy, begins 15–30 min after meals
Food fear (sitophobia)	Leads to reduced intake
Weight loss	Due to chronic under-eating
Nausea, bloating, early satiety	From gastric hypoperfusion or visceral hypersensitivity
Abdominal bruit (epigastric)	Midline; louder during expiration

Imaging Evaluation

Modality	Imaging features
CTA	• Focal proximal narrowing of celiac artery (Hook-shaped or J-shaped indentation)
• Post-stenotic dilatation: Common in dynamic compression
• Dynamic variation: Worsens on expiration, improves on inspiration
• Diaphragmatic crura indentation: Seen on sagittal reformatted images
• Normal SMA/IMA: Helps exclude generalized mesenteric ischemia
USD	• Peak systolic velocity (PSV) >200 cm/s at the celiac origin
• Worsens on expiration, improves on inspiration
• May also show a characteristic spectral "notching" pattern
MRA	• Similar findings as CTA
• Avoids radiation and iodinated contrast
• Limited dynamic assessment
DSA	• Rarely required for diagnosis
• May be used pre-intervention or for surgical planning