[Plagiocephaly associated with infant asymmetry].

The typical asymmetry in infancy is recognized 2-4 weeks after birth and follows the development of a plagiocephaly. The unilateral flattening of the occiput leads to a permanent rotation of the head to one side, shortening of neck muscles and a triggering of the asymmetric tonic neck reflex (ATNR), also known as fencer response. Subsequently a muscle tone increase is forming on the side of the face while a decrease in tone is seen at the occiput side. Clinical signs like increasing neck stiffness, flexible positional scoliosis and pelvic obliquity may ultimately develop. Management includes early positioning, tummy time and physical therapy if asymmetry of posture or muscle tone are present.