Parietale

Parietale, or os parietale (the parietal bone), is one of the paired bones that form the roof and sides of the cranium. Each parietal bone contributes to the calvaria, enclosing the brain, and lies between the frontal bone anteriorly and the occipital bone posteriorly, with the temporal and sphenoid bones at its sides.

The parietal bones articulate with other skull bones along sutures: the coronal suture with the frontal bone, the sagittal suture where the two parietal bones meet, the lambdoid suture with the occipital bone, and the squamous sutures with the temporal bones. The sphenoid bone also forms part of the skull vault near the pterion region. The external surface is convex and bears a parietal eminence near the center, with superior and inferior temporal lines marking muscle attachments for the temporalis. The internal surface is concave and contains grooves for the middle meningeal vessels and impressions related to dural structures, such as the region around the superior sagittal sinus.

Developmentally, the parietal bones arise from intramembranous ossification and are typically formed from two membranous plates that fuse along the sagittal suture. In infants, fontanelles allow growth of the brain and skull; the posterior and anterior fontanelles gradually ossify during early childhood.

Etymology traces to Latin os parietale, meaning “of the wall.” In anatomy, parietal (from paries, wall) is used to describe the skull bones that form the cranial vault.