In a baby, the skull (cranium) is
made up of several plates of bone, which lie side by side, but are not
actually joined. In normal circumstances, these plates expand and grow,
allowing the baby’s brain to grow inside the skull. Eventually, when the brain has
finished growing in early adulthood, all the plates of bone
will join together (fuse) at their seams (sutures) so that the skull
becomes a fixed “box” of bone, which protects the brain.
In
Craniosynostosis,
one or more of the seams (sutures) has joined too early. This happens
before birth, but is not caused by anything the mother did or did not do
during pregnancy. The baby is born with an unusual shaped head. This is
because the skull cannot grow properly in the area that has fused too
early. The baby’s brain needs to grow rapidly during the first year of
life, so there may be extra growth in another area of the skull to
compensate for the restriction in the affected area. This may accentuate
the abnormal skull shape.
The shape of the baby’s head
will depend on which suture has fused early.
Some babies may have other
abnormalities as well, such as webbing of fingers and toes, (syndactyly)
or inability to breathe through the nose (choanal atresia).