BACKGROUND Pneumomediastinum is an uncommon clinical condition that usually occurs spontaneously, or is caused by blunt thoracic or abdominal trauma. This report is of a rare case of pneumomediastinum caused by blunt neck trauma in an adult and describes the clinical and radiological features and the principles of clinical management. CASE REPORT A 23-year-old man presented with increased neck swelling, dysphonia and pain on swallowing (odynophagia) after blunt neck trauma during a rugby game. Chest X-ray and computed tomography (CT) showed features that were consistent with pneumomediastinum, including extensive subcutaneous emphysema. The patient was intubated and monitored in the intensive care unit (ICU) and managed with early stabilization of the airway and with conservative methods. He had no complications on clinical follow-up following hospital discharge. CONCLUSIONS Although pneumomediastinum is an uncommon condition, the complications can be fatal. This case highlights the importance of thoroughly investigating cases of subcutaneous emphysema and the importance of early stabilization of the airway.