One of the leading causes of abnormal head shape deformity in newborn babies is Torticollis (wryneck). Torticollis is a result of muscle stiffness/shortness in the neck. It develops from an imbalance in the neck muscles. Infants with Torticollis cannot make a full rotation of their neck from one direction to another due to the unevenly developed muscles. It is estimated that 85-90% of cases of deformational plagiocephaly are associated with Torticollis or some form of neck discomfort.
Typically, the heads of infants suffering from Torticollis bend to one side and the head rotates towards the opposite shoulder, so that the head is permanently resting only on one side. Flatness occurs behind the head because the head stays in the same position all the time. The ear shifts because of the pressure on the same direction of the backside of the head where the flatness occurs. In severe cases, the forehead can also be pushed forward on the same side, and facial features including the eyes, cheeks and jaw may not be symmetrical.