AN25.1-9 | Thorax — Summary & Reflection

REFLECT

A 40-year-old domestic worker presents with chronic right-sided chest pain. On examination: dullness to percussion at the right base with absent breath sounds. CXR shows a homogeneous opacity at the right base with a concave upper border (meniscus sign). How do you use your knowledge of pleural anatomy and surface markings to interpret this CXR? Where would you insert a chest drain?

KEY TAKEAWAYS

Thorax — Key Points:

1. Thoracic vertebrae: costal demifacets on body + costal facet on transverse process (T1–T10)
2. Ribs 1–7 = true (direct sternal attachment); 8–10 = false; 11–12 = floating
3. Intercostal VAN runs in costal groove — insert needles OVER upper border of lower rib
4. Diaphragm openings: T8 (IVC + right phrenic), T10 (oesophagus + vagal trunks), T12 (aorta + thoracic duct)
5. Phrenic nerve = sole motor supply (C3, C4, C5). Referred pain → shoulder tip (C4)
6. Thoracic inlet = T1 + first rib + manubrium; cervical rib → thoracic outlet syndrome
7. Surface: apex beat = 5th ICS MCL; rib notching = coarctation; paradoxical movement = flail chest