A pleural effusion is the collection of liquid in the pleural space; the tendency of liquid is to collect at the base or posterior of the lung. Therefore, the provider will insert the chest tube posteriorly in the fifth intercostal space. Pneumothorax, or collection of air in the pleural space, is evacuated by a chest tube placed anteriorly in the third intercostal space. This location is chosen because air rises. Posteriorly, third intercostal space, and anteriorly, fifth intercostal space, are not common sites for chest tube insertion for pleural effusion pneumothorax.