Traumatic extrathoracic lung herniation is an exceptional complication of blunt chest trauma. We report the case of a 46-year-old man who was involved in a motorcycle accident and who suffered a left clavicle fracture-dislocation associated with multiple rib fractures and massive herniation of the left upper lobe through an upper anterior chest wall defect. Immediate surgical repair through an atypical transcostal vertical thoracotomy resulted in full recovery of pulmonary function at 1 year.