Posterior Basal Pulmonary Segment

Description

Posteriorly within the lower lobe, the posterior basal bronchopulmonary segment (Segmentum basale posterius, often termed the postero-basal segment) occupies the dorsal and inferior portion of the lung parenchyma, tapering toward the diaphragmatic surface. Its segmental bronchus and accompanying pulmonary artery branch course centrally within the segment, while intersegmental pulmonary veins run in the connective tissue septa that mark its boundaries with adjacent basal segments. Superiorly it relates to the superior (apical) segment of the lower lobe, and laterally it approaches the costal surface under the posterior ribs. A clear segmental map. Accurate localization of the posterior basal segment matters when disease is not lobar but segmental. Aspiration pneumonia and dependent atelectasis often track to the posterior basal segments in supine patients, and bronchiectasis can remain confined to a single segment along the path of its segmental bronchus. Segment-oriented planning also guides bronchoscopy, CT reporting, and lung-sparing surgery: a posterior basal segmentectomy relies on identifying the segmental bronchovascular pedicle and following intersegmental veins to define the resection plane without compromising neighboring basal segments. Pulmonology and thoracic surgery educators can drop this graphic into bronchopulmonary segment lectures, case-based radiology modules, and operative anatomy atlases to reinforce consistent terminology across bronchoscopy reports and cross-sectional imaging. It also fits well in clinical pathway documents for aspiration risk, lower-lobe atelectasis, or segmental resection planning in early-stage peripheral lung cancer. Anatomical accuracy verified by SciePro's Medical Advisory Board.