Lungs and Bronchopulmonary Segments
The lungs are subdivided into functionally independent bronchopulmonary segments, each supplied by a tertiary (segmental) bronchus and a branch of the pulmonary artery.
Lobes and Fissures
- Right Lung: Three lobes (superior, middle, inferior). Has both an oblique fissure and a horizontal fissure.
- Left Lung: Two lobes (superior, inferior). Has only an oblique fissure. Features the lingula, a tongue-like projection of the superior lobe homologous to the middle lobe of the right lung.
Key Clinical Relevance
| Concept | Clinical Detail |
|---|---|
| Segmental Autonomy | Each segment is surgically resectable without disrupting the function of adjacent segments. |
| Aspiration | Foreign bodies are more likely to enter the right lung due to the wider, shorter, and more vertical orientation of the right main bronchus. |
High-Yield Exam Pearl:
The position of an aspirated object depends on the patient’s posture:
• Supine: Enters the superior segment of the right lower lobe or the posterior segment of the right upper lobe.
• Upright: Tends to enter the right lower lobe (basal segments).