Final answer:
The term associated with a scene size-up for a traumatic injury is 'mechanism of injury', which is critical in helping predict potential injuries and determining the index of suspicion.
Step-by-step explanation:
The term associated with a scene size-up and used in assessing a patient who has received a traumatic injury is mechanism of injury. The mechanism of injury refers to how the injury occurred and includes an understanding of the forces involved that could potentially cause harm to the patient. It's an essential aspect of emergency medical services and helps in predicting the index of suspicion for certain types of injuries based on the nature of the trauma. For example, a high-speed car crash may raise suspicion for spinal or head injuries. On the other hand, the nature of illness typically refers to a patient's medical condition that is not caused by an external trauma.
\