Interdural transcavernous approach to the upper clivus. The anterior wall of the cavernous sinus has been opened, and the cavernous segment of the ICA and the right inferior hypophyseal artery (IHA) exposed. The medial wall of the cavernous sinus and the pituitary gland are displaced medially to expose the posterior clinoid. Venous bleeding is controlled with gentle packing and hemostatic agents. The transcavernous approach provides an excellent view of the posterior clinoid. The IHA, which arises from the cavernous ICA, runs over the posterior clinoid, and gives branches to the dorsum and floor of the sella, to finally reach the posterior lobe of the pituitary gland. (Image courtesy of JC Fernandez-Miranda)