Final answer:
The nurse observes the client's behavioral pain response, shown by guarding the fractured arm and avoiding movement to protect it.
Step-by-step explanation:
The nurse notes the client's reaction of guarding his arm and refusal to move as a type of behavioral pain response. During a pain assessment, various responses can be observed, which help the healthcare provider understand the nature and extent of the pain experienced by a patient. Guarding an injured part of the body, like an arm with a fracture, is a behavioral indicator that the patient is experiencing pain and is trying to protect the area from further harm or discomfort.
This kind of response is often involuntary and protective in nature, meant to minimize movement and prevent exacerbation of the pain. Behavioral responses to pain are important to recognize as they can provide insights into how much pain the person is in and how it is affecting their daily activities.