Frontiers of Trauma-Crash Phases and Energy Exchange

Here are some preparation notes for cross examination of defense medical expert in a significant impact personal injury case:

Trauma. In trauma the history is the injured person’s story of the impact and the energy exchanged from the impact. To evaluate traumatic injury we must begin with an understanding of the crash phases.

A traumatic event is divided into three phases: 1) Pre crash phase: 2) Crash phase; and 3) Post crash phase.

Pre Crash Phase. This is where we analyze the condition of the person before the traumatic event. Acute or pre existing conditions must be taken into account. A traumatic event is often more injury producing to a person with pre existing conditions such as degenerative disk disease. As we say if we are lucky we get old;   when we get old we get degeneration like degenerative disk disease. So if we are lucky we have degenerative disk disease. The down side is we are less able to handle a traumatic event. Other pre crash considerations include the body position before trauma, expectancy  and gender.

The Crash Phase. “The crash phase begins at the time of impact between one moving object and a second object. The second object can be moving or stationary and can either be an object or a person.” Kinematics of Trauma at 45. In a motor vehicle collision three impacts occur: 1) the impact to the vehicles; the impact to the people in the vehicles; and 3) the impact to the organs inside the people. For example, in a motor vehicle  collision the first impact is the collision between the vehicles. The second impact is to the occupants such as striking the seat belt, the air bag, the head rest or the inside of the vehicle. The third impact is to the occupant’s internal organs and chest wall, abdominal wall  and skull. Id.

The Post Crash Phase. This phase begins with the care of the injuries. The post crash continues for a lifetime in a permanent personal injury case.

Energy Exchange. In any traumatic injury case it is important to evaluate and understand the energy exchange. This allows us to get a handle on the forces involved in the traumatic event. Medical providers and juries relate well to cases involving the exchange of significant force. This is because there is a common sense relationship between the exchange of significant force and injury. Here we need to visit basic laws of motion.

The Law of Conservation of Energy and Newton’s Second Law of Motion. “The law of conservation of energy combined with Newton’s second law of motion describes that energy cannot be created or destroyed but can be changed in form.” Id. Applied to an automobile collision, the motion of the colliding vehicles is energy. When the vehicles collide their energy is dissipated by the bending of their bodies. Energy is then dissipated inside the vehicles as occupant bodies strike objects inside the vehicle. Energy dissipation continues inside the structures of the bodies of the occupants as their organs stop their forward motion against the chest wall, abdominal wall and skull. This translates to personal injury.

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