Anatomy of a Newborn Baby's Skull
The skull may seem to be 1 large bone, but it's made of several major bones that are
connected together. The major bones that compose the skull include:
2 frontal bones
2 parietal bones
1 occipital bone
These bony plates cover the brain, and are held together by fibrous material called
What are sutures?
Sutures allow the bones to move during the birth process. They act like an expansion
joint. This allows the bone to enlarge evenly as the brain grows and the skull expands.
The result is a symmetrically shaped head. Some sutures extend to the forehead, while
others extend to the sides and back of the skull. One suture in the middle of the
skull extends from the front of the head to the back. The major sutures of the skull
Metopic suture. This extends from the top of the head down the middle of the forehead, toward the
nose. The 2 frontal bone plates meet at the metopic suture.
Coronal suture. This extends from ear to ear. Each frontal bone plate meets with a parietal bone plate
at the coronal suture.
Sagittal suture. This extends from the front of the head to the back, down the middle of the top of
the head. The 2 parietal bone plates meet at the sagittal suture.
Lambdoid suture. This extends across the back of the head. Each parietal bone plate meets the occipital
bone plate at the lambdoid suture.
If any of the sutures close too early (fuse prematurely), there may be no growth in
that area. This may force growth to happen in another area or direction. This results
in an abnormal head shape (craniosynostosis).
What are fontanelles?
A fontanelle is the space between the bones of a baby's skull where the sutures intersect.
There are 2 fontanelles. These spaces are covered by tough membranes (dura) that protect
the underlying soft tissues and brain. The fontanelles include:
Anterior fontanelle (also called soft spot). This is the junction where the 2 frontal and 2 parietal bones meet. The anterior fontanelle
remains soft until about 18 months to 2 years of age. Doctors can assess if there
is increased intracranial pressure by feeling the anterior fontanelle.
Posterior fontanelle. This is the junction of the 2 parietal bones and the occipital bone. The posterior
fontanelle usually closes first, before the anterior fontanelle, during the first
several months of an infant's life.
Because the fontanelles are soft early in life, it is easy to take pictures of a baby's
brain with ultrasound.