The paired parietal bones form much of the cranial vault and articulate with all the other flat bones of the skull.
Sutures – In birth, the junctions between the flat bones of the skull cannot be fused in order for the baby to pass through the birth canal. This leaves uncalcified areas present to allow for head growth. These are known as the anterior and posterior fontanelles or in common parlance, “soft spots.” As these calcify, they leave behind prominent sutures between the partial bone and the other flat bones. These sutures have names and can be seen in the diagrams. The sagittal suture is found between the left and right parietal bones, the lambdoid suture is between the occipital bone and the two parietal bones, the coronal suture is between the frontal bone and the parietal bones and on each side there is a squamosal suture between the parietal bone and the temporal bone.
Markings – Besides the sutures the superior and inferior temporal lines are found on the parietal bone. The superior line is the origin of the connective tissue that surrounds the temporalis muscle and the inferior line is the superior limit of the muscle attachment for the temporalis muscle. This origin of this muscle is quite large and the lines extend anteriorly onto the frontal bone and inferiorly onto the temporal bone.