Where is chest tube insertion typically performed?

• A. 4th or 5th intercostal space in the mid-axillary line
• B. 2nd intercostal space midclavicular
• C. 7th intercostal space anterior axillary line
• D. 9th intercostal space posterior axillary line

Answer: (A)

Placing a chest tube to drain air or fluid is done through the lateral chest wall where the pleural space is most accessible and safe to reach. The typical entry is in the mid-axillary line around the 4th or 5th intercostal space. This location provides a direct path into the pleural cavity while staying high enough to avoid the abdominal organs and low enough to avoid the heart, and you insert the tube over the upper edge of the lower rib to protect the intercostal vessels that run along the inferior rib border. This approach aligns with the safe triangle boundaries, which guide a practical and safer route for drainage. Other sites are less ideal for a standard chest tube: for example, the second intercostal space at the midclavicular line is usually reserved for emergent needle decompression in tension pneumothorax, while lower or more posterior positions increase the risk of injuring abdominal organs or being difficult to access effectively.