Posterior basal segment of right lung

The posterior basal segment of the right lung (S10) is one of the five bronchopulmonary segments of the right lower lobe. It is a discrete, functionally and anatomically independent unit of lung parenchyma, each bronchopulmonary segment being supplied by its own segmental bronchus (B10), segmental artery (A10), and drained by intersegmental veins.

Anatomical Definition and Relationships

The posterior basal segment (S10) occupies the posteroinferior portion of the right lower lobe, resting against the posterior chest wall and the diaphragm. Its key anatomical relationships include:

• Superiorly: bordered by the superior segment (S6) of the right lower lobe.

• Medially: adjacent to the medial basal segment (S7).

• Laterally: bordered by the lateral basal segment (S9).

• Anteriorly: related to the anterior basal segment (S8).

Bronchovascular Anatomy

• The segment is ventilated by the posterior basal segmental bronchus (B10), which arises from the basal trunk of the right lower lobe bronchus. B10 typically divides into subsegmental branches (B10a, B10b, B10c).

• The posterior basal segmental artery (A10) courses dorsally and deeply into the lung parenchyma, making it one of the more challenging segmental arteries to identify surgically because it does not directly face the interlobar fissure or hilum.

• Venous drainage is via tributaries of the inferior pulmonary vein, with segmental veins running along the intersegmental planes.