A baby's skull consists of five thin, curved bony plates that
are held together by fibrous material called sutures. The skull
is soft enough so that it can expand as a baby's brain grows.
Usually, the area within a baby's skull doubles in the first 6
months of life and doubles again by age 2. Some sutures begin to
close at about this time. After age 2, the skull and brain grow
at a much slower rate. The sutures gradually harden (ossify) to
join the skull bones together. The spaces where sutures meet are
called fontanelles or "soft spots." If any of the sutures close
too early, it may affect normal skull development, sometimes
resulting in a misshapen head or other problems. Babies born
with certain conditions may have irregular fontanelles and
sutures. For example, a baby born with congenital hydrocephalus
may have wider sutures than normal, and the tissue covering the
fontanelles may bulge. How this information was developed to
help you make better health decisions.