Colored Apicoposterior Segment of the Left Lung, Posterior View

Description

Positioned in the upper left hemithorax, the apicoposterior bronchopulmonary segment (segmentum apicoposterius, S1+S2) of the left upper lobe is isolated in color and presented from a posterior, slightly superior viewpoint. Its parenchyma occupies the superoposterior contour of the lung, lying superior to the oblique fissure and posterior to the anterior segment of the upper lobe (S3). Medially, the segment approaches the mediastinal surface near the hilum, while laterally it forms a substantial portion of the convex costal surface near the apex. Apicoposterior anatomy matters because this segment is a frequent site of reactivation tuberculosis and other posterior upper-lobe processes that track along ventilation patterns and gravitational gradients. On posterior chest radiographs and CT, lesions here can be mistaken for apical pleural thickening or scapular overlap unless you can mentally project the segment’s boundaries relative to the oblique fissure and hilum. Segmentectomy planning also depends on this map, since S1+S2 often shares a combined bronchus and arterial supply in the left lung, and fissure completeness influences the operative approach and risk of postoperative air leak. Small territory, big surgical consequences. Use this illustration in thoracic anatomy teaching for medical and PA curricula, in radiology correlation modules that pair segmental maps with axial CT, and in thoracic surgery publications discussing left upper-lobe segmentectomy, VATS port placement, and bronchovascular dissection strategy. It also fits pulmonary pathology lectures that localize cavitary disease, aspergilloma, or aspiration-related scarring to posterior upper-lobe segments. Anatomical accuracy verified by SciePro's Medical Advisory Board.