Presentation
Medical fitness chest x-ray performed for overseas study.
Patient Data
Distinct appearanes of a thin line of pleura extending from the upper mediastinum towards the right lung apex.
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.