10 downloadssdhas - stl file processed, cta, axial, dicom, 3d, model, stl, pulmonary, trunk, bronchial, lung, spinal, dorsal, vessels, heart This file was created with democratiz3D. Automatically create 3D printable models from CT scans. Learn more. The right mainstem bronchus divides into the right upper lobe bronchus and the bronchus intermedius (BI). The former then divides into 3 segments: apical (RB1), posterior (RB2), and anterior (RB3). The bronchus intermedius divides into the right middle lobe and right lower lobe bronchi. The right middle lobe bronchus has two segments: lateral (RB4) and middle (RB5). The right lower lobe bronchus has 5 segments: superior (RB6), medial basal (RB7), anterior basal (RB8), lateral basal (RB9), and posterior basal (RB10). The left mainstem bronchus divides into the left upper lobe and lower lobe bronchi. The left upper lobe bronchus subsequently divides into the left upper division bronchus and the lingular division. The former gives rise to 3 segments: apical (LB1), posterior (LB2), and anterior (LB3). The apical and posterior segments are usually fused in a single apicoposterior (LB1/2) segment. The lingular bronchus has 2 segments: superior lingular (LB4) and inferior lingular (LB5). The left lower lobe bronchus branches into the superior (LB6), anteromedial basal (LB7/8), lateral basal (LB9), and posterior basal (LB10) segments.