Azygo-esophageal recess

Last revised by Joshua Yap on 27 Apr 2023

The azygo-esophageal recess (AER), also known as the azygo-esophageal line or interface, is a prevertebral space formed by the interface of the posteromedial segments of the right lower lobe and the azygos vein and esophagus 1-3. The azygo-esophageal recess extends from the azygos arch to the aortic hiatus and has the following borders 1,2:

Radiographic features

Plain radiograph

It appears as a straight stripe running from the azygos arch to the level of the right hemidiaphram, but can normally deviate 1-3:

  • upper third: a rightward convexity may be normal in children and young adults

  • middle third: may be slightly leftward convex relative to the right lung near the hilum

  • lower third: usually straight

Related pathology

Deviation of the azygo-esophageal recess can also be due to disease in the middle or posterior mediastinum. 

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Cases and figures

  • Figure 1: annotated chest x-ray
    Drag here to reorder.