AZYGOUS FISSURE, VEIN AND LOBE

1. AZYGOS FISSURE, VEIN, AND LOBE
An azygos lobe is created when a laterally
displaced azygous vein makes a deep fissure in
the upper part of the lung during embryological
development. It is therefore not a true accessory
lobe, but rather a normal variant appearance of
the right upper lobe, which results
from invagination of the azygos vein.

2. AZYGOS FISSURE, VEIN, AND LOBE
Azygos fissure represents one of the accessory
fissures of lung, which is a normal developmental
variant. It is of no clinical significance to the
patient. The fissure creates an accessory lobe
(azygos lobe) of the lung.

3. AZYGOS FISSURE, VEIN, AND LOBE
Azygos lobe is usually well seen on the chest
radiograph, where it is limited by azygous
fissure - a fine, convex (relative to the
mediastinum) line that crosses the apex of the
right lung.

4. AZYGOS FISSURE, VEIN, AND LOBE
Azygos vein, which is lined by visceral and
parietal pleura, lies in the base of fissure.
Medially there is a small connection of the
'azygos lobe' with the rest of the upper lobe.

5. AZYGOS FISSURE, VEIN, AND LOBE
Azygos fissure has a tadpole shape, the
azygos vein itself forming head of tadpole.
Because azygos vein is a right-sided
structure, this accessory fissure is only ever
seen on the right side of the chest.

6. AZYGOS FISSURE, VEIN, AND LOBE
A lobe of the azygos vein
appears in the right lung in
about 1 percent of people.
It develops when the apical
bronchus grows superiorly
medial to the arch of the
azygos vein instead of
lateral to it. As a result, the
azygos vein comes to lie at
the bottom of a deep
fissure in the superior lobe
of the right lung. Therefore,
the azygos fissure contains
four layers of pleura.