Case Study: Cant Move Right Arm

2-year-old girl was swinging on a jungle gym at park.

Pain localized to elbow and  unable to lift right arm

No swelling, deformity, or focal tenderness

Normal appearance, normal breathing, normal circulation

What are the possible differential  diagnoses?

How should you proceed with your exam? Diagnostic tests? Treatment?

* I know that the July 4th holiday falls on Monday- so I gave you an extra couple of days to post. Have a Happy 4th!