Fact-sheet: Tracheal bronchus
Updated on 05/21/2024 at 6:11 PM
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Definition
Anatomic variant of the bronchial tree defined by the supracarinal origin of an accessory bronchus.
Strong right-sided predominance compared to the left side
Clinical features
Most often an incidental finding
Occasionally: recurrent right upper lobe pneumonia and focal overdistension.
CT
Unenhanced chest CT, analyzed with coronal reconstructions using lung windowing.
Allows analysis of the level of origin of the accessory bronchus, and determination of whether it is a displaced bronchus (the bronchus normally supplying the corresponding segment is absent) or a supernumerary bronchus (the bronchus supplying the segment is present).
The pig bronchus is defined as a displaced right tracheal bronchus supplying the entire right upper lobe
Classification
Conacher classification
Type 1: origin > 2 cm from the carina with underlying tracheal narrowing (false carina appearance with an origin angle of approximately 30°).
Type 2: origin > 2 cm from the carina without underlying tracheal caliber abnormality
Type 3: origin close to the carina (<2 cm). This type includes carinal trifurcation