The parietal bone is a paired bone located on each side of the skull behind the frontal bone. Both parietal bones together form most of the calvaria. Each parietal bone has an irregular convex quadrilateral shape with four angles, four margins and two surfaces.

Angles

Frontal angle - anterior superior angle
Sphenoidal angle - anterior inferior angle (the sharpest angle)
Occipital angle - posterior superior angle
Mastoid angle - posterior inferior angle

Margins

Frontal margin - forms the anterior border
Occipital margin - forms the posterior border
Squamous or temporal margin - inferior margin
Sagittal margin - upper, medial margin

Surfaces and landmarks

The parietal bone has an external and an internal surface.

The external surface is convex and features the following landmarks:

Parietal tuber - it is also called parietal eminence; prominence located near the middle of the external surface of the parietal bone; it is the most convex part;
Superior temporal line - a curved sagittal direction oriented line for attachment of the temporal fascia; it also represents the upper margin of the temporal plane;
Inferior temporal line - a curved sagittal direction oriented line for attachment of the temporal muscle; it is situated below the superior temporal line;
Parietal foramen - an opening occasionally present at the back part of the parietal bone near the occipital angle and sagittal margin; it serves as a passage for the parietal emissary vein, which drains into the superior sagittal sinus.

The internal surface of the parietal bone is concave and features:

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Parietal bone