Final answer:
The nurse should assess the patient's range of motion and functionality before obtaining a trapeze bar for a patient with limited mobility.
Step-by-step explanation:
Prior to obtaining a trapeze bar for a patient with limited mobility, the most important assessment for the nurse to obtain is an assessment of the patient's range of motion and functionality. The nurse should assess the patient's ability to perform movements such as abduction, adduction, circumduction, flexion, and extension of the affected joint. This assessment will help determine the extent of the patient's mobility limitations and inform the decision to provide a trapeze bar or explore other options.