The Skull of a Newborn
Brand new babies often have ridges on their skulls that you can feel under the skin. These ridges are supposed to be there.
Our skulls are not smooth like an egg, but are actually made up of plates of bone. The spaces where the plates come together are called sutures. At birth the sutures are really important to allow the baby's skull to change shape during birth. A baby's brain grows really fast, and the skull must expand to accommodate the growing brain. The skull-bone growth takes place at the sutures.
It is possible for babies to have skulls where some of the sutures are missing (craniosynostosis). If this happens, the baby's skull doesn't grow right, and he may even need surgery so the skull can expand to fit the growing brain.
The soft spot (fontanelle) is where three or four plates of bone come together. Your baby has one in the front of his skull and one in the back. They are not really soft or tender. They are covered with very tough tissue, like the gristle on a chicken bone. It does not harm your baby to touch his soft spots. When your baby is very still, you may see his pulse in his soft spot. That is because there is tremendous blood supply to his growing brain. It is normal and OK.
Thanks to Janelle Aby MD, Stanford School Of Medicine, Newborn Nursery, and Lucille Packard Children's Hospital for the use of occasional photographs.