Chest radiograph of an adult patient presenting with chest pain and shortness of breath. This is an AP examination. Evidence of previous cardiac mediastinotomy. The lungs are hyperinflated. Air is seen within the mediastinum. Surgical soft tissue emphysema is also identified. Appearance on imaging is suggestive of pneumomediastinum. No lung lesions appreciated. No pneumothorax. No rib fractures identified. Differential diagnosis for the pneumomediastinum include ruptured oesophagus, trauma or iatrogenic injury from instrumentation. This is a emergency. I would convey the findings to the referring team.