Chances are she liked fine needles in her syringes - less pain and a smaller pin prick hole. The length of the needle depends on if you are injecting under the skin or into a muscle. But neither one needs to be very long unless you are going to go into the butt muscle. You can inject into any muscle (thigh muscle - stomach muscle - calf muscle - etc).
Hmmm - Dr. Baden saying that the Demerol was in pill form (how does he know?).....and that even if there had been a single injection - that Dr. Perper would have seen this on the initial examination.