As yоu pоsitiоn аn аdult pаtient for a skull examination, you begin to position a shadow shield attached to the x-ray tube assembly to protect the patient’s thyroid from exposure. While you are doing so, the lead shield falls and hits the patient in the throat. You apologize, and nursing care is administered to the patient. Eventually, the patient’s voice changes, and they contend that the accident led to their throat damage. In the court proceedings, the patient’s attorney claims negligence and uses the principle of