The four major sutures of the skull are the coronal, sagittal, lambdoid, and squamous sutures. Sutures connect the frontal, parietal, temporal, and occipital bones of the skull and allow movement during birth by acting as expansion joints that enable even growth of the bones and brain. There are also two fontanelles between the skull bones, the anterior and posterior fontanelles, which are soft spots in an infant's skull that close during the first two years of life.

1. The four major sutures are the coronal, sagittal, lambdoid, and squamous sutures. They connect
the frontal, parietal, temporal, and occipital bones.
The coronal suture joins the frontal bone to the parietal bones.
The sagittal suture joins the two parietal bones to each other.
The lambdoid suture joins the parietal bones to the occipital bone.
The squamous suture joins the parietal bones to the temporal bones.
Although the skull appears to be one large bone, there are actually several major bones that
are connected together. The major bones that compose the skull of a newborn include the
following:
2 frontal bones
2 parietal bones
1 occipital bone
These bony plates cover the brain and are held together by fibrous material called sutures.
What are sutures? 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 include the following:

2. metopic suture - extends from the top of the head down the middle of the forehead,
toward the nose. The two frontal bone plates meet at the metopic suture.
coronal suture - extends from ear to ear. Each frontal bone plate meets with a parietal
bone plate at the coronal suture.
sagittal suture - extends from the front of the head to the back, down the middle of the
top of the head. The two parietal bone plates meet at the sagittal suture.
lambdoid suture - extends across the back of the head. Each parietal bone plate meets
the occipital bone plate at the lambdoid suture.
Sutures allow the bones to move during the birth process. They act like an expansion joint,
allowing the bone to enlarge evenly as the brain grows and the skull expands, resulting in a
symmetrically shaped head. However, if any of the sutures close too early (fuse prematurely),
there may be no growth in that area. This may force growth to occur in another area or direction,
resulting in an abnormal head shape.
What are fontanelles? There are two fontanelles (the space between the bones of an infant's
skull where the sutures intersect) that are covered by tough membranes. The fontanelles include:
anterior fontanelle (Also called soft spot.) - the junction where the two frontal and two
parietal bones meet. The anterior fontanelle remains soft until about 2 years of age.
posterior fontanelle - the junction of the two 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.