Deformational Plagiocephaly - the most common type of 'Infant flat head syndrome'
- The most common type of skull deformity in infants
- Normally noticed by caregivers at about six to 10 weeks of age
- Characterised by an asymmetrical skull shape
- Unilateral occipital flattening
- Ear is positioned more anterior on the side of the occipital flattening
- Forehead may be asymmetrical and is positioned more anterior on the side of the occipital flattening
- Facial asymmetry may be present
- May be accompanied by torticollis, limited neck range of motion, weakness and preferential head positioning
What are the main causes of Plagiocephaly?
The push to put babies to sleep on their back to reduce the risk of sudden infant death syndrome (SIDS) has been associated with a decrease in the incidence of SIDS but has led to an increase in the number of babies living with head shape abnormalities. Long hours in the supine position causes prolonged external pressure to an infants head.
Congenital muscular torticollis: This is a deformity resulting from shortening/fibrosis of the sternocleidomastoid muscle (SCM) and is associated with plagiocephaly in almost 90% of infants. Because of this shortening, the infant maintains support of the head on only one side, tilting the head toward the side of the affected muscle and turning the chin to the opposite side.
Multiple fetuses is related to a higher incidence of risk factors, primarily due to the fact that the “crowded” uterus means an intrauterine constraint, a factor related to deformities present at birth. It is believed that when the baby is positioned at a lower position in the uterus, there seems to be a higher risk of developing an asymmetrical skull. As the baby needs to support more weight, the mobility and capacity to change position can adversely predispose to congenital torticollis.
Changes in our current lifestyle may also have contributed to the factors of postnatal deformational or positional plagiocephaly. The use of firm mattresses, frequent use of seats (in the car and for recreation, also known as babybouncers), and swings often cause the baby to stay for long periods in the supine position. The extensive use of the seat accessories would determine a greater potential to deform the skull.
Other contributing risk factors for head deformation
- Prolonged exposure to the supine position
- Lack of time on the tummy when the baby is awake
- Congenital muscular torticollis, neck weakness or restricted neck range of motion
- Males more frequently develop deformational plagiocephaly at a rate of 2:1
- Slower motor development particularly in gross motor skills
- Breech or transverse presentation
- Multiple birth infants
- Visual field deficits
- Bony abnormality in the cervical spine
Why are the skulls of infants subject to deformation?