Transcranial Dissection of the Sellar and Parasellar Region. The 1-mm perforations are enhanced with green circles for clarity. A, After brain removal, the dura mater covering the right anterior clinoid process has been removed. B, The right anterior clinoid process has been drilled, view of the 3 reference points (6, 7, 8) of the lateral opticocarotid recess corresponding to the optic strut. Note the point corresponding to the deepest and middle part of the tuberculum recess (1). The proximal and distal dural rings and the carotidoculomotor membrane are exposed. The middle clinoid process is not visualized as it is located below the level of the posterior junction of the proximal and distal dural rings at the tip of the anterior clinoid. C, The dural rings have been incised to retract laterally the right carotid artery, and the periosteal layer of the dura mater has been removed. The medial opticocarotid point (4) and caroticosellar point (5) are exposed with the middle clinoid (yellow dotted line). The caroticosellar and medial opticocarotid points are superior to the middle clinoid. D, Bilateral dissection showing both junction points and bilateral prominent middle clinoid processes. (Images courtesy of AL Rhoton, Jr.)