Bronchopulmonary segments (left lung)

Normally, there are ten bronchopulmonary segments in the left lung. These are described by a standard nomenclature: individual segments are numbered from the apex of the lung passing inferiorly.

In a large percentage of the population:

• there is an accessory bronchopulmonary segment, the subapical segment, in the inferior lobe
• the apical and posterior bronchopulmonary segments may arise from a separate division of the superior lobar bronchus, the apicoposterior segmental bronchus. Each segment forms by a division of this bronchus distally, but the entire volume of lung supplied by the apicoposterior segmental bronchus is often termed the apicoposterior segment.