The paired Os parietale is a skull bone that forms part of the calvaria. It forms the roof and the largest part of the lateral wall of the skull.
Anatomy
Internal surface
The internal surface of the Os parietale is referred to as the Facies interna and is concave. The Arterial grooves can be delineated on the Facies interna; they are caused by the Middle meningeal artery and its branches. In addition, the Sulcus sinus sigmoidei can be found on the internal surface; it is formed by the Sigmoid sinus and is located near the Angulus mastoideus. Medially, the Sulcus sinus sagittalis superioris is located; it is caused by the Superior sagittal sinus.
External surface
The external surface of the Os parietale is referred to as the Facies externa and is convex. The Linea temporalis superior and inferior are located on the Facies externa; the fascia temporalis and the cranial portion of the Musculus temporalis attach there. In some cases, a Foramen parietale may also be present on the external surface; a Vena emissaria parietalis passes through it and connects the Sinus sagittalis superior with veins of the scalp.