Normal azygos arch: retrotracheal visualization on frontal chest tomograms

Area of Science:

• Radiology
• Anatomy

Background:

• The azygos arch is a common anatomical structure in the chest.
• Variations in its course can mimic pathological findings.

Purpose of the Study:

• To describe the normal anatomical variations of the azygos arch.
• To aid in differentiating normal variants from abnormalities.

Main Methods:

• Anteroposterior linear tomograms of 78 adult subjects.
• Analysis of pleural reflections off the retrotracheal azygos arch.

Main Results:

• Azygos arch visualized in 49% of subjects.
• Five distinct patterns of the azygos arch course were identified.
• Variations were mainly dependent on the inferior margin's position.

Conclusions:

• Understanding normal azygos arch variations is crucial.
• This knowledge helps prevent misdiagnosis of retrotracheal abnormalities.