Excessively large fontanelles are larger than expected soft spots for the age of a baby. In an infant, the spaces where the bones of the skull come together, but are not completely joined, are called soft spots or fontanelle (fontanel or fonticulus).

Soft spot - large

Fontanelles allows for growth of the skull during an infant's first year. Slow or incomplete closure of the skull bones is most often the cause of a wide fontanelle.

For general information, see fontanelles.

Larger than normal fontanelles are most commonly caused by:

• Achondroplasia
• Down syndrome
• Hydrocephalus
• Intrauterine growth retardation (IUGR)
• Prematurity

Rarer causes:

• Apert syndrome
• Cleidocranial dysostosis
• Congenital rubella
• Neonatal hypothyroidism
• Osteogenesis imperfecta
• Rickets

Images

Skull of a newborn

Large fontanelles (lateral view)

Fontanelles

Large fontanelles

Next Section

Fontanelles Treatment

Review Date: 11/02/2009
Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)