Parietal Foramen

*Temporal Aperture* - The opening of the parietal bone is formed by the medial surfaces of the parietal and temporal bones, the openings of the squama of the temporal bone, the temporal and occipital bones.

Boundaries of the parietal aperture or foramen are bone landmarks: - External: the inner surface of the squama of the parietal bone, the anterior edge of the thenar fossa of the temporal bone to the roof of the skull along the umbrella line. Along the edge from the top of the thenar foramen downwards within the bony base lie the lateral foramen magnum, the internal occipital protuberance, and the carotid arteries. - Internal: diploic bone covered by the inner surface of the squamosal and parietal membrane of the parietal bone. The border is limited inferiorly by the thenar prominence