left principal (primary)
      upper lobar (secondary)
            anterior segmental (tertiary)
            apical-posterior segmental (tertiary)
            inferior lingular segmental (tertiary)
            superior lingular segmental (tertiary)
       lower lobar (secondary)
            anterior-medial basal segmental (tert)
            lateral basal segmental (tertiary)
            posterior basal segmental (tertiary)
            superior segmental (tertiary)