[TA] smallest surgically resectable subdivision of the lobes of the lungs, supplied exclusively by a tertiary (segmental) bronchus and the corresponding tertiary branch of the pulmonary artery (segmental pulmonary artery); typically, the right lung has ten bronchopulmonary segments, and the left has eight or nine due to a merging of the apical and posterior segments of the upper lobe and of the anterior and medial basal segments of the lower lobe. SYN: segmentum bronchopulmonale [TA].