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Right crus of diaphragm

The right crus of the diaphragm is a musculotendinous structure arising from the anterior surfaces of the upper three lumbar vertebral bodies (L1–L3) and their intervertebral discs. It is longer and larger than the left crus and contributes to the formation of the esophageal hiatus. Fibers of the right crus ascend superiorly and medially before inserting into the central tendon of the diaphragm. The right crus surrounds the esophageal hiatus in a sling-like fashion, helping regulate the passage of the esophagus and vagus nerves through the diaphragm and acting as an anatomical component of the lower esophageal sphincter mechanism.

Synonyms

  • Crus dextrum diaphragmatis

  • Right diaphragmatic crus

  • Vertebral part of the diaphragm (right side)

Function

  • Provides anchoring support for the diaphragm to the lumbar spine

  • Contributes to formation and regulation of the esophageal hiatus

  • Plays a role in preventing gastroesophageal reflux via diaphragmatic contraction

  • Assists in respiration, stabilizing the diaphragm during contraction

  • Helps maintain intra-abdominal and intrathoracic pressure differences

MRI Appearance

T1-weighted images:

  • Right crus appears as a low-signal intensity muscular structure arising from the lumbar vertebrae

  • Surrounded by hyperintense fat planes of retroperitoneum, which provide contrast

  • Useful for identifying hypertrophy or distortion of the crus in hiatal hernia or tumors

T2-weighted images:

  • Crus remains low to intermediate signal intensity due to muscle content

  • Adjacent fat is hyperintense, enhancing definition

  • Pathology (edema, inflammation, or invasion) may appear hyperintense relative to normal fibers

STIR (Short Tau Inversion Recovery):

  • Fat suppression improves contrast between crus and retroperitoneal fat

  • Normal crus remains low signal; edema, inflammation, or tumor infiltration appears bright hyperintense

T1 Post-Contrast (Gadolinium-enhanced):

  • Normal crus shows mild homogeneous enhancement

  • Abnormal thickening, infiltration, or tumors show asymmetric or heterogeneous enhancement

CT Appearance

Non-contrast CT:

  • Right crus appears as a muscular soft tissue density arising from the anterolateral aspects of L1–L3 vertebrae

  • Clearly delineated against surrounding retroperitoneal fat and abdominal viscera

  • Appears thicker and longer than the left crus

Contrast-enhanced CT (CECT):

  • Enhances mildly and homogeneously with intravenous contrast

  • Clearly shows the esophageal hiatus formed by crus fibers

  • Best for detecting crural thickening (e.g., hiatal hernia, fibrosis, or tumor infiltration)

MRI image

Right crus of diaphragm anatomy MRI axial image -img-00000-00000

CT image

Right crus of diaphragm anatomy CT axial image -img-00000-00000