A nasogastric tube coiled within the left hemithorax
A right pleural effusion
Elevated left hemidiaphragm
Mediastinal shift towards the left
Abdominal contents passing into the right hemithorax via a right diaphragmatic rupture will push the mediastinal structures towards the left. Hollow viscera within the chest are more commonly seen in a left diaphragmatic rupture as the liver will tend to obstruct the passage of abdominal contents into the chest (the same will apply for a nasogastric tube).