"However, the absence of crying does not mean a child is not in pain. An infant in severe pain may not cry at all, especially if he is premature or very young. He may simply not have the energy to cry.

Despite these typical movements, premature and very young babies may not move and may become still. This absence of movement has also been noted in older children recovering from surgery. They recognize that moving hurts and so remain still to minimize the amount of pain."