## Bronchopulmonary Segments of the Right Lung **Key Point:** The right lung has 10 bronchopulmonary segments, divided into three lobes. The apical segmental bronchus supplies the apical segment (S1), which is the most superior segment of the right upper lobe. ### Right Upper Lobe Segments | Segment | Number | Bronchus | Location | | --- | --- | --- | --- | | Apical | S1 | Apical segmental | Superior, posterior | | Posterior | S2 | Posterior segmental | Superior, posterior | | Anterior | S3 | Anterior segmental | Superior, anterior | **High-Yield:** The apical segment (S1) is clinically important because it is the most common site of tuberculosis reactivation due to its high oxygen tension and relatively poor lymphatic drainage. **Clinical Pearl:** When examining the right upper lobe on a chest X-ray, the apical segment occupies the apex and extends posteriorly. Lesions in this segment are often missed on frontal views and require lateral views for confirmation. **Mnemonic:** APL = **A**pical (S1), **P**osterior (S2), **L**ower anterior (S3) for right upper lobe segments. 
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