The first MRI I had was an Open Bore MRI machine and it was on my hip so I went in feet first. The second one was a regular one and it was on my shoulder so head first. They started putting me in there and I was freaking out. I thought it was funny because they told me to breathe shallowly so I wouldn't move the shoulder. However, I was practically hyperventilating (I'm slightly claustrophobic). The only thing that helped me through was that I figured that I had enough room to get out by wiggling like an inchworm. the next MRI I had I made sure I got to go to the Open Bore MRI again.
After being in the little MRI machine, I was talking to my orthopedic surgeon (who used to be an NFL offensive lineman) and asking him how football players got MRIs. He said that he could only fit his shoulders in if he lifted his arms above his head.