AN24.1-6 | Lungs & Trachea — Summary & Reflection

REFLECT

A 70-year-old retired weaver presents with progressive breathlessness and bilateral pleural effusions. CXR shows small lungs with reticular opacities. His occupation involved exposure to cotton dust for 40 years. Which pleural layers are involved? What type of pleural disease do you suspect? How does knowledge of the costodiaphragmatic recess explain the CXR findings?

KEY TAKEAWAYS

Lungs & Trachea — Key Points:

1. Trachea: C6 → carina (T4/T5); C-rings open posteriorly (trachealis muscle); right bronchus wider/shorter/more vertical
2. Right lung: 3 lobes (upper, middle, lower), 10 bronchopulmonary segments; oblique + horizontal fissures
3. Left lung: 2 lobes, 8–10 segments; oblique fissure only; lingula = middle lobe equivalent
4. Hilum: bronchus, pulmonary artery, 2 pulmonary veins, bronchial vessels, lymphatics, nerves
5. Dual blood supply: pulmonary (gas exchange, right heart → left atrium) + bronchial (nutritive, aorta)
6. Pleura: visceral (no pain) + parietal (pain); costodiaphragmatic recess = most dependent, fills first
7. Lung base (erect): 6th rib MCL, 8th MAL, 10th paravertebral; pleura extends 2 ribs lower