Cruciform eminence

The cruciform eminence refers to the cross-shaped arrangement of bony grooves for various venous sinuses found on the inner surface of the squamous part of the occipital bone. This surface is concave, with a bony bump in the center known as the internal occipital protuberance. Starting from this bump, we find two grooves extending sideways for the right and left transverse sinuses, one groove going upward for the superior sagittal sinus, and another groove moving downward along the internal occipital crest for the occipital sinus. Together, these four grooves divide the concave inner surface of the squamous part of the occipital bone into four fossae: two upper cerebral fossae (which contain the occipital lobes of the brain) and two lower cerebellar fossae (which contain the cerebellar hemispheres).