I, Midsagittal section of the sella extending through the anterior and posterior lobes and sphenoid sinus. The intercavernous carotid produces prominences in the lateral wall of the sphenoid sinus below and anterior to the gland. The sella extends forward to the anterior edge of the intracavernous carotid only if greatly expanded by tumor. Intercavernous sinuses courses along the anterior and posterior margin of the diaphragm. The basilar sinus, located on the back of the dorsum, is the largest connection across the midline between the posterior edge of the paired cavernous sinuses. The inferior hypophyseal artery arises from the posterior bend of the intercavernous carotid and is directed medially toward the posterior lobe. J, Posterosuperior view of another gland deeply indented on its lateral surface by the intercavernous carotid. A tongue of gland extends laterally above the artery. The anterior clinoid has been removed and the nerves in the wall of the cavernous sinus exposed. K, Anterior view of another gland. The cavernous sinuses are located on the lateral side of the gland and separate the gland from the intracavernous carotids. The superior hypophyseal arteries arise from the medial side of the supraclinoid carotid and pass to the chiasm and stalk. The anterior intercavernous sinus crosses the anterosuperior margin of the gland, and the inferior intracavernous sinus extends below the gland interconnecting the cavernous sinuses. L, The optic nerves and chiasm have been elevated to expose the pituitary stalk, superior hypophyseal, and ophthalmic arteries. M, Another gland and sella viewed from superiorly. The diaphragm partially covers the upper surface of the gland, but the opening in the diaphragm is larger than the pituitary stalk. The posterior lobe (not shown) was entirely hidden below the dorsum sellae. An intercavernous sinus passes across the upper anterior surface of the gland. N, Superior view of another gland exposed below a large natural opening in the diaphragm. (Images courtesy of AL Rhoton, Jr.)