Parietal Bone

Meningeal Grooves

Grooves that are 'middle meningeal arteries' that dominate the endocranial surface of the parietal. These arteries supply the 'dura mater'. The most anterior branch parallels the coronal edge of the parietal, and most of the branches traverse the bone toward its occipital angle.

Siding the Parietal

Siding is difficult only when the parietal bone is very fragmentary. The meningeal grooves are oriented vertically along the coronal suture and more horizontally near the squamous suture. -The coronal suture, unlike the sagittal suture, is an interdigitating, rather than an interlocking, zipper-like, or jigsaw like articulation. The large anterior middle meningeal vessel makes an impression along this suture endocranially. -The thickest corners are the occipital and mastoid angles. -The mastoid angle bears a sulcus endocranially. -The squamous suture is lateral and inferior, and the parietal striae angle posterosuperiorly.

Frontal Angle

The 'practically right-angle' where which each side of the nose deviates from the vertical. This is specifically located at the Bregma.

Mastoid Angle

The angle is where the lambdoidal suture connects to the temporal. This is located at the asterion. It is truncated and presents on its inner surface a broad, shallow groove which lodges part of the transverse sinus.

Sphenoidal Angle

The angle where the frontal, parietal and temporal bones connect. This is located at the pterion. This piece is thin and acute, and is received into the interval between the frontal bone and the great wing of the sphenoid. Its inner surface is marked by a deep groove, sometimes a canal, for the anterior divisions of the middle meningeal artery.

Occipital Angle

The rounded angle with the intersection of sagittal and lambdoidal sutures. This is located at the lambda.

Parietal Striae

The striations or "rays" that pass posterosuperiorly for some distance on the ectocranial surface of the parietal from their origin on its beveled squamous edge.

Temporal Lines

These arch anteroposteriorly across the parietal and frontal bones which dominate the ectocranial surface. There are also the Superior and Inferior Temporal Lines. (I wasn't able to find a picture through Quizlet, so here's the link to what the Temporal Lines look like- https://en.wikipedia.org/wiki/Temporal_line#/media/File:Temporal_line_-_animation01.gif)

Parietal Eminences

These lie on the widest part of the cranium. It is the large, rounded eminence centered on the ectocranial surface of the parietal. It marks the center of ossification of the bone.

Sigmoid Sulcus

These sulcus, also known as sulcus for the sigmoid or the transverse sinus, crosses the mastoid angle of the parietal, cutting a groove on the endocranial surface. It marks the course of the transverse, or sigmoid sinus, which is a vessel that drains blood from the brain.

Sagittal Sulcus

This is made when the parietals are articulated and the shallow grooves along the sagittal edge of each parietal combine along the endocranial midline. The sulcus is a posterior continuation of the same feature on the frontal. This feature is also apart of the parietal and occipital bones.

Parietal Foramen

When present, this is located close to the sagittal suture near lambda. It transmits a small vein through the parietal to the superior sagittal sinus. It is located specifically at the Obelion.