Claudios Galen (119-199 a.d.) dissected lower animals with parasellar carotid retia bathed in venous blood and transposed his findings to human anatomy. Andreas Vesalius (1514-1564) corrected most of Galen's errors but apparently never looked into this small, extradural compartment, nor, apparently, did Winslow (Exposition Anatomique de la Structure du Corps Humain. London: N. Prevast, 1734), who christened it the "cavernous sinus," (CS) presumably thinking that it would resemble the corpora cavernosa of the penis. Multiple surgical explorations, gross dissections, microscopic views, and vascular casts from early fetuses to an 81 year old have been examined and reviewed. The CS is not a dural sinus nor is it cavernous. The compartment is extradural, and the venous structures contained within consist of a greatly variable plexus of extremely thin-walled veins. The name, CS, is a barrier to the understanding of the structure and function of this extradural anatomical jewel box, which contains fat, myelinated and nonmyelinated nerves, arteries, and a plexus of veins. It is proposed that this name be changed, because it is inaccurate and misleading. The replacement should leave no doubt about its meaning. The lateral sellar compartment is descriptive and accurate. The veins within are a parasellar plexus.