How is plagiocephaly treated?

Therapy or helmet : Kids with plagiocephaly favor sleeping on one ear & end up with stiffness or shortening of the sterno-cliedo-mastoid muscle on one side. Over time, always sleeping the same way allows gravity to trigger the skull deformity. If caught early, parents can maneuver the head to both sides to help resolve the issue. Some get distorted enough to need a helmet with special pads to help reshape the skull.

Yes, in infants.: Flat back of the head is called plagiocephaly. The most common cause by far is babies laying on their backs. "back to sleep" is the right thing to do as this clearly prevents sudden infant death syndrome. Usually the flat head will self resolve with less time spent on the back, or helmeting can be considered if the problem is severe.