Scope of practice question

Yesterday my patient who had a mostly negative CT of the spine had a flex-ex x-ray ordered to clear the c-spine. Both the charge nurse and the neurosurg resident told me that it was OK for me to take off the collar and hold c-spine during the flexion and extension so I felt really pressured to do it and did it (at least I had EMS experience and knew how). It all went smoothly but I still don't feel right about having done it. Does anyone know if it's in our scope of practice as nurses to do this?

I understand that the risk was pretty low in my patient (Ct and all) BUT I didn't like how the charge nurse was like "oh we do it all the time". She didn't even know how to hold c-spine correctly herself. I am just a traveller so I am going to keep my mouth shut but I was really uncomfortable about the whole situation.