Penetrating chest trauma results from an object entering through the skin and chest wall into the chest cavity. Examples include gunshot, stab, and fragment wounds.

Blunt chest trauma results from the impact of an object or an energy force on the chest wall such as in a motor vehicle crash, being struck in the chest with a bat, or a blast injury. In some instances, such as a blast from an improvised explosive device (IED), you may encounter a casualty with both blunt and penetrating chest trauma. Both blunt and penetrating chest trauma can be lethal.

Seeing a bruise or a gunshot wound on the chest can help you assess the casualty and the mechanism of injury. Getting under body armor and uniforms to assess a casualty is easier said than done. There will be times when you will have to rely on the mechanism of injury and the casualty's presentation to identify if they have a life-threatening injury.