Facies interna ossis parietalis

The internal surface is concave; it presents depressions corresponding to the cerebral convolutions, and numerous furrows (grooves) for the ramifications of the middle meningeal artery; the latter run upward and backward from the sphenoidal angle, and from the central and posterior part of the squamous border.

Along the upper margin is a shallow groove, which, together with that on the opposite parietal, forms a channel, the sagittal sulcus, for the superior sagittal sinus; the edges of the sulcus afford attachment to the falx cerebri.

Near the groove are several depressions, best marked in the skulls of old persons, for the arachnoid granulations (Pacchionian bodies).

In the groove is the internal opening of the parietal foramen when that aperture exists.