In which groove of a rib does the neurovascular bundle of the intercostal space run?

Explanation

## Anatomical Location of Intercostal Neurovascular Bundle **Key Point:** The intercostal neurovascular bundle (artery, vein, and nerve) runs in the **inferior groove (costal groove)** of each rib, protected by the rib above. ### Protective Anatomy The costal groove is a shallow depression on the **inferior surface** of the rib that houses: - Intercostal artery (runs between internal and external intercostal muscles) - Intercostal vein (lies superior to the artery) - Intercostal nerve (lies inferior to the artery and vein) **Mnemonic:** **VAN** — **V**ein, **A**rtery, **N**erve (from superior to inferior within the groove) ### Clinical Significance **Clinical Pearl:** When performing a thoracentesis or chest tube insertion, the needle is directed **superior to the rib** to avoid injury to the neurovascular bundle that runs in the costal groove of the rib below. **High-Yield:** The neurovascular bundle runs along the **inferior margin** of each intercostal space, making the **superior aspect of the lower rib** the safest entry point for procedures. ### Why the Groove Location Matters The inferior groove provides: - Protection from external trauma - Anatomical containment within the intercostal fascia - Clear separation from the external intercostal muscles above [cite:Gray's Anatomy 42e Ch 54]