Thoracic injuries are the second leading cause of death in pediatric trauma patients. Most are due to blunt trauma. However, in recent years, there has been an increase of penetrating trauma in children in the United States. Children have a small, cylindrical-shaped chest which is compliant due to incomplete calcification of bones and thinner layers of muscle and fatty tissue. This offers little protection to the chest cavity and thoracoabdominal organs. There is an increased incidence of pulmonary and cardiac contusions and a decreased incidence of rib fractures and flail chest, compared to adults.

Children have a more mobile mediastinum, which can lead to pronounced shifts with increased thoracic pressure in the setting of tension pneumothorax.