SymptomsBy Mayo Clinic staff
CLICK TO ENLARGE
|Cranial sutures and fontanels|
Your infant's skull has seven bones. Normally, these bones don't fuse until around age 2, giving your baby's brain time to grow. Joints called cranial sutures, made of strong, fibrous tissue, hold these bones together. In the front of your baby's skull, the sutures intersect in the large soft spot (fontanel) on the top of your baby's head. Normally, the sutures remain flexible until the bones fuse.
Craniosynostosis signs in general
Signs of craniosynostosis include:
- A misshapen skull, with the shape depending on which of the cranial sutures are affected
- An abnormal feeling or disappearing "soft spot" (fontanel) on your baby's skull
- Slow or no growth of the head as your baby grows
- Development of a raised, hard ridge along affected sutures
- Increased pressure within the skull (intracranial pressure)
The signs of craniosynostosis may not be noticeable at birth, but they will become apparent during the first few months of your baby's life.
Main categories and characteristics
There are two categories of craniosynostosis:
- Primary craniosynostosis. If your baby has primary craniosynostosis, one or more of the cranial sutures become rigid, fusing the connecting bones and inhibiting the brain's ability to grow normally.
- Secondary craniosynostosis. With secondary craniosynostosis, your infant's brain stops growing, usually due to an underlying hereditary syndrome, allowing the sutures to fuse prematurely.
Common types and characteristics
The most common types of craniosynostosis are:
- Sagittal synostosis (scaphocephaly). Premature fusion of the suture at the top of the head (sagittal suture) forces the head to grow long and narrow, rather than wide. Scaphocephaly is the most common type of craniosynostosis.
- Coronal synostosis (anterior plagiocephaly). Premature fusion of a coronal suture — one of the structures that run from each ear to the sagittal suture on top of the head — may force your baby's forehead to flatten on the affected side. It may also raise the eye socket and cause a deviated nose and slanted skull.
- Bicoronal synostosis (brachycephaly). When both of the coronal sutures fuse prematurely, your baby may have a flat, elevated forehead and brow.
Rare types and characteristics
Two less common types of craniosynostosis are:
- Metopic synostosis (trigonocephaly). The metopic suture runs from your baby's nose to the sagittal suture. Premature fusion gives the scalp a triangular appearance.
- Lambdoid synostosis (posterior plagiocephaly). This rare form of craniosynostosis involves the lambdoid suture, which runs across the skull near the back of the head. It may cause flattening of your baby's head on the affected side.
Misshapen head may not mean craniosynostosis
A misshapen head doesn't always indicate craniosynostosis. For example, if the back of your baby's head appears flattened, it could be the result of your baby's sleeping on his or her back.
The "Back to Sleep" campaign, co-sponsored by the National Institute of Child Health & Human Development, encourages parents to put healthy babies to sleep on their backs to reduce the risk of sudden infant death syndrome (SIDS). But, this has also resulted in more cases of misshapen heads. In this case, the flattening is not serious because it's a result of positional molding, not craniosynostosis.
When to see a doctor
Contact your pediatrician if you think your baby's head isn't growing as it should or if it has an unusual shape.
- Craniosynostosis information page. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/craniosynostosis/craniosynostosis.htm. Accessed Aug. 9, 2011.
- Stal S, et al. Overview of craniosynostosis. http://www.uptodate.com/home/index.html. Accessed Aug. 9, 2011.
- Craniosynostosis and craniofacial disorders. American Association of Neurological Surgeons. http://www.aans.org/en/Patient%20Information/Conditions%20and%20Treatments/Craniosynostosis%20and%20Craniofacial%20Disorders.aspx. Accessed Aug. 9, 2011.
- Back to Sleep public education campaign. National Institute of Child Health & Human Development. http://www.nichd.nih.gov/sids. Accessed Aug 9, 2011.
- Stal S, et al. Craniosynostosis syndromes. http://www.uptodate.com/home/index.html. Accessed Aug. 9, 2011.