Tracheal bronchus with regional ventilation and perfusion abnormalities.

Tracheal bronchus is an uncommon anomaly of the tracheobronchial tree. In the case presented, clinical and pathophysiologic abnormalities were associated with this anomaly. The tracheal bronchus supplied the right upper lobe of the lung. The bronchus intermedius arose directly from the trachea in place of the right main bronchus. It was accompanied by marked regional changes in ventilation and perfusion. We discuss the clinical significance of this unusual anomaly.