Apicoposterior Segmental Bronchus of the Left Lung, Anterior View

Description

Arising from the left upper lobar (secondary) bronchus, the apicoposterior segmental bronchus (B1+2, bronchus segmentalis apicoposterior) courses superiorly and posteriorly toward the apicoposterior segment of the left upper lobe, yet it is still appreciable from an anterior projection. From this angle, it lies superior to the lingular bronchi (B4 and B5) and superior-lateral to the left lower lobar bronchus, with its segmental takeoff oriented more cranially than the anterior segmental bronchus (B3). Expect adjacent fissural context: the oblique fissure demarcates upper from lower lobe, and the mediastinal contour sits medially toward the hilum. Small airway. Big implications. Segmental anatomy matters because bronchoscopy, bronchial blocker placement, and segmentectomy planning all depend on precise identification of B1+2 in the left lung, where apical and posterior segments frequently share a common stem rather than separate B1 and B2 branches. This view supports teaching of why left upper lobe resections often reference a fused apicoposterior bronchus and why endobronchial spread of infection or tumor can remain confined to a bronchopulmonary segment bounded by its segmental bronchus. It also helps correlate with CT, where B1+2 is traced from the left upper lobar bronchus into the apicoposterior parenchyma along the segmental artery. Pulmonary fellows and thoracic surgeons can use this anterior-oriented rendering in bronchoscopy manuals, thoracic surgery texts, and slide decks covering left upper lobe segmentectomy (S1+2) and hilar anatomy, while radiology educators can pair it with axial CT examples to reinforce segmental bronchial labeling. An apt choice for anatomy courses that move beyond lobes into bronchopulmonary segments and clinically relevant variants. Anatomical accuracy verified by SciePro's Medical Advisory Board.