What position is best for demonstrating the presence of free air in the right hemithorax?

The best position for demonstrating the presence of free air in the right hemithorax is the left lateral decubitus position. In this position, the patient is lying on their left side, which allows any free air that may be present in the pleural space to rise to the highest point, typically the right side of the thorax, due to the effects of gravity.

When a patient is in the left lateral decubitus position, free air will accumulate in the area around the diaphragm on the right side, making it easier for imaging studies, such as X-rays, to reveal the presence of air. This is crucial in identifying conditions such as pneumothorax or perforation of abdominal organs leading to free air in the thoracic cavity.

The other positions would not effectively demonstrate free air in the right hemithorax. For example, if the patient is in a supine position, free air would not rise to a location clearly observable on the imaging. Similarly, the right lateral decubitus position would cause any free air in the right hemithorax to move away from the detector, and the prone position would not provide a clear view of the air in the right hemithorax. Thus, the left lateral dec