Azygos lobe

Case contributed by Dr Ian Bickle


Medical fitness chest x-ray performed for overseas study.

Patient Data

Age: 20
Gender: Female

Distinct appearanes of a thin line of pleura extending from the upper mediastinum towards the right lung apex.

Annotated image

Arrows indicate the azygos fissure resulting in a small azygos lobe.  No separate bronchial supply.

Case Discussion

An azygos lobe is one of, if not the most commmonest, anatomical variants observed on plain chest x-ray.

An azygos lobe is created when a laterally displaced azygos vein makes a deep pleural fissure into the apical segment of the right upper lobe during embryological development. It is due to invagination of the azygos vein and pleura during foetal development.

It is not a true accessory lobe as it does not have its own bronchus.

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Case information

rID: 45706
Case created: 5th Jun 2016
Last edited: 30th Jun 2016
System: Chest
Tag: rapids
Inclusion in quiz mode: Included

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