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Median arcuate ligament

The median arcuate ligament (MAL) is a fibrous arch formed by the union of the right and left crura of the diaphragm, crossing anterior to the aortic hiatus at the level of T12 vertebra. It forms the superior border of the aortic hiatus, through which the aorta, thoracic duct, and azygos vein pass. In most individuals, the ligament lies just above the origin of the celiac trunk; however, in some cases, it crosses low and compresses the celiac artery, producing median arcuate ligament syndrome (MALS), characterized by postprandial abdominal pain, weight loss, and nausea.

Synonyms

  • MAL

  • Fibrous diaphragmatic arch

  • Median arcuate diaphragmatic ligament

Function

  • Forms the superior border of the aortic hiatus

  • Provides a fibrous attachment between the crura of the diaphragm

  • Contributes to stabilization of the diaphragm during respiration

  • May play a role in vascular compression syndromes when abnormally low in position

MRI Appearance

T1-weighted images:

  • The MAL appears as a low signal intensity (hypointense) fibrous band anterior to the aortic hiatus

  • Surrounded by intermediate to high signal fat, allowing good contrast

  • Compression of the celiac artery may be seen as narrowing of its proximal portion

T2-weighted images:

  • Ligament remains low signal intensity (fibrous structure)

  • Surrounding fat and vascular structures are bright, providing contrast

  • May show abnormal contour or indentation on the celiac artery

STIR (Short Tau Inversion Recovery):

  • MAL remains low signal

  • Surrounding edema or inflammatory changes (if present in compression syndrome) appear hyperintense

T1 Post-Contrast (Gadolinium-enhanced):

  • MAL itself does not enhance

  • Contrast highlights the celiac artery, showing focal narrowing with post-stenotic dilatation if compression is significant

CT Appearance

Non-contrast CT:

  • Seen as a thin, soft tissue density band crossing anterior to the aorta at the diaphragmatic crura

  • May be difficult to visualize without contrast

Contrast-enhanced CT (CT Angiography):

  • Best modality to demonstrate MAL and its relationship to the celiac trunk

  • Shows characteristic focal narrowing of the proximal celiac artery with a hooked appearance in compression

  • Post-stenotic dilatation may be present in severe cases

  • Respiratory variation: narrowing often more pronounced on expiration

MRI image

Median arcuate ligament anatomy MRI axial image -img-00000-00000

CT image

Median arcuate ligament anatomy CT axial image -img-00000-00000

CT images

Median arcuate ligament ct axial image

CT images

Median arcuate ligament ct coronal image

MRI images

Median arcuate ligament MRI axial image anatomy image -img-00000-00000

MRI images

Median arcuate ligament MRI coronal image anatomy image -img-00000-00000

MRI images

Median arcuate ligament MRI sag image anatomy image -img-00000-00000