Right posterior pulmonary contusion particularly within the lower lobe. Associated right lower lobe pulmonary interstitial emphysema with air tracking into the mediastinum (pneumomediastinum). This mechanism of blunt traumatic pneumomediastiunum is known as the Macklin effect. Trace air below the heart in the epicardial fat explains the continuous diaphragm sign seen on x-ray. Small right pneumothorax predominantly anterobasally and trace left apical pneumothorax also present.