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Azygoesophageal line

The azygoesophageal line is a normal curvilinear radiographic interface seen on frontal chest radiographs. It represents the interface between the right lung and the mediastinal structures, primarily the esophagus and azygos vein, within the azygoesophageal recess.

It is an important mediastinal contour used in chest X-ray interpretation to assess normal anatomy and mediastinal symmetry.

Synonyms

  • Azygoesophageal recess line

  • Right posterior mediastinal line

Location

  • Seen along the right side of the lower thoracic spine

  • Extends from the level of the azygos vein arch

  • Continues inferiorly toward the diaphragmatic hiatus

  • Located in the posterior mediastinum

  • Medial to the right lower lung field

Anatomical basis

  • Right lung forming the lateral boundary

  • Esophagus forming the medial component

  • Azygos vein contributing superiorly

  • Posterior mediastinal pleura creating the air–soft tissue interface

Relations

Laterally:

  • Right lower lobe of the lung

Medially:

  • Esophagus

Superiorly:

  • Azygos vein arch

Inferiorly:

  • Esophageal hiatus of the diaphragm

Posteriorly:

  • Thoracic vertebral bodies

Anteriorly:

  • Posterior mediastinal soft tissues

X-ray appearance

Chest radiograph (PA view):

  • Appearance: Smooth, gently curving vertical or slightly oblique line

  • Contour: Convex toward the right lung

  • Margins: Sharp and well-defined

  • Extent: From the azygos arch superiorly to near the diaphragm inferiorly

  • Visibility: Best seen on well-inspired, properly exposed films

  • Normal variation: Mild curvature changes depending on lung inflation and patient positioning

CT image

Azygoesophageal line ct Anatomy, Location and Imaging Appearance CT anatomy image -img-00000-00000

X-Ray image

Azygoesophageal line x ray Anatomy, Location and Imaging Appearance CT anatomy image -img-00000-00000