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Right lumbar part of diaphragm

The right lumbar part of the diaphragm is a muscular portion of the diaphragm that arises from the vertebral column via the right crus. It is larger and stronger than the left lumbar part, reflecting the presence of the liver on the right side. It contributes to the formation of the esophageal hiatus and surrounds the aortic hiatus together with the left crus.

This part of the diaphragm plays a major role in respiration and also serves as an important anatomical structure in the retroperitoneum, in close relation to the sympathetic chain, aorta, inferior vena cava, and thoracolumbar vertebrae. Its integrity is vital in preventing diaphragmatic hernia and ensuring normal respiratory function.

Synonyms

  • Right diaphragmatic crus

  • Lumbar diaphragm (right side)

  • Right vertebral part of diaphragm

Origin, Course, and Attachments

  • Origin: Arises from the anterior surfaces of the bodies of L1 to L3 vertebrae and the intervening intervertebral discs

  • Course:

    • Fibers ascend vertically and medially from their vertebral origins

    • The fibers join the central tendon of the diaphragm after encircling key retroperitoneal structures

  • Attachments:

    • Strong muscular slips anchored to the vertebral column

    • Contributes to the margins of the aortic hiatus (at T12) and esophageal hiatus (at T10)

Relations

  • Anteriorly: Inferior vena cava, right adrenal gland, posterior surface of liver

  • Posteriorly: Bodies of L1–L3 vertebrae and anterior longitudinal ligament

  • Medially: Left crus and median arcuate ligament

  • Laterally: Psoas major and quadratus lumborum muscles

Function

  • Major muscle of respiration, contributing to diaphragmatic contraction and descent during inspiration

  • Helps form the esophageal hiatus, contributing to prevention of gastroesophageal reflux

  • Maintains separation of thoracic and abdominal cavities

  • Provides muscular support to adjacent retroperitoneal and mediastinal structures

Clinical Significance

  • Hiatal hernia: Weakness or enlargement of the right crus may contribute to paraesophageal or sliding hiatal hernia

  • Tumor spread: Retroperitoneal tumors or lymphadenopathy can invade or compress the lumbar diaphragm

  • Surgical relevance: Key landmark during retroperitoneal, vascular, or thoracoabdominal surgeries

  • Imaging: Important in differentiating true diaphragmatic defects from normal muscular slips on MRI and CT

MRI Appearance

T1-weighted images:

  • Appears as a low-to-intermediate signal muscular structure

  • Surrounded by bright retroperitoneal and mediastinal fat, improving delineation

T2-weighted images:

  • Demonstrates intermediate to mildly hyperintense signal compared to muscle

  • Borders with adjacent fat and retroperitoneal structures well outlined

  • Pathological thickening or edema appears brighter

T1 Fat-Sat Post-Contrast:

  • Normal right lumbar diaphragm shows mild homogeneous enhancement

  • Pathological processes (tumor infiltration, inflammation, infection) appear as focal or diffuse enhancement

3D T2 SPACE / CISS:

  • Shows the right lumbar diaphragm as a thin, moderately hyperintense muscular band relative to muscle

  • Clearly contrasts against bright CSF in adjacent spinal canal and surrounding fat

  • Excellent for visualizing relationships with the aorta, IVC, sympathetic chain, and hiatuses

CT Appearance

Non-Contrast CT:

  • Appears as a soft tissue density band arising from L1–L3 vertebrae and ascending to central tendon

  • Fat planes between diaphragm, kidney, and adrenal gland help define its margins

Post-Contrast CT:

  • Enhances mildly and homogeneously

  • Pathological changes (tumor, inflammation, metastasis) cause focal or diffuse thickening with variable enhancement

MRI images

Right lumbar part of diaphragm mri coronal anatomy image-img-00000-00000

MRI images

Right lumbar part of diaphragm axial