Expansion
Apicoposterior, anterior, superior and inferior lingular; superior and three or four basal segments
Expansion
Upper lobe
- Apicoposterior - apical and posterior fused
- Anterior
- Superior lingular
- Inferior lingular
Lower lobe
- Superior
- Anteromedial basal - anterior and medial basal commonly fused
- Lateral basal
- Posterior basal
That gives 8 segments, though some classifications separate the fused pairs and count up to 10.
The lingula is the left-sided counterpart of the right middle lobe, but it belongs to the upper lobe rather than forming a lobe of its own, a direct consequence of the heart occupying the space where a middle lobe would otherwise sit.