The upper lobe bronchus separates immediately into a lingular bronchus (B⁴⁺⁵) and a common stem that usually branches into an anterior bronchus (B³) and an apicoposterior bronchus (B¹⁺²) (◘ Fig. 15.1a). B¹⁺² lies in a groove whose boundaries are the lingular artery and the truncus anterior. Identifying B³ usually requires lifting up B¹⁺². Contrary to the right side, variations in the division and distribution of segmental bronchi are rare. However, B¹ and B² can rise separately (◘ Fig. 15.1b).

A¹ and A² arteries originate in the fissure and distribute themselves over the curve of the pulmonary artery. A¹ is the most superior one and should not be confused with A³ (◘ Fig. 15.1c and d).

In most cases, the superior pulmonary vein has three major tributaries: the superior branch drains S¹ and S² segments (^V1+2). The middle branch (V³) drains S³, and the inferior branch (^V4+5) drains the lingula.