OverviewA wide fontanelle occurs when the fontanelle is larger in size than expected for the age of the baby. Slow or incomplete ossification of the skull bones is most often the cause of a wide fontanelle.
Update Date 12/4/2013
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.