Superior view of tentorial notch area with brain removed. The anterior cranial fossa is shown at the top of the image. In the midline is the crista galli of the ethmoid bone for attachment of the falx cerebri and the laminae cribrosa (cribriform plates) on either side, on which lie the olfactory bulbs. The middle cranial fossae are the depressions along the right and left borders. The sella turcica is located in the midline and contains the pituitary gland. It consists of the tuberculum sellae anteriorly and the dorsum sellae posteriorly. The diaphragma sellae overlies the gland with an aperture in its roof that transmits the pituitary stalk to the hypothalamus. The intercavernous sinuses are visible within the diaphragma connecting the right and left cavernous sinuses. Lateral to the tuberculum sellae are the optic nerves and internal carotid arteries. The tentorium cerebelli attaches anteriorly to the clinoid processes of the sphenoid and laterally to the superior border of the petrous temporal bone. Its medial edge is free and forms the lateral boundary of the tentorial notch for passage of the brainstem into the posterior cranial fossa. The oculomotor nerve penetrates the dura covering the roof of the cavernous sinus just lateral to the posterior clinoid process of the dorsum sellae (not labeled). It courses to the orbit through the superior orbital fissure. The trigeminal nerve pierces dura near the apex of the petrous bone. The abducens nerve pierces clival dura and ascends in a superomedial direction toward the petrous apex where it passes below the petrosphenoid ligament to enter the cavernous sinus. (Image courtesy of M Nunez)