Final answer:
An ER nurse practitioner should assess a boy who fell and cannot walk, order an x-ray to diagnose the injury, and formulate a treatment plan based on the x-ray results.
Step-by-step explanation:
The scenario described involves a young boy who has fallen from a playground structure and is unable to walk. As an emergency room (ER) nurse practitioner, the appropriate action would be to conduct a physical assessment and then order diagnostic imaging, such as an x-ray, to determine the extent of the injury. The primary concern would be to rule out any fractures or bone dislocations that could be responsible for the inability to walk. Once the x-ray results are available, a treatment plan can be formulated, which may include immobilization, casting, surgery, or referral to a specialist such as an orthopedic surgeon.