Diaphragm Sellae, Inferior View

Description

Seen from the intracranial inferior aspect, the diaphragm sellae forms a horizontal dural fold spanning the sella turcica, with its central aperture transmitting the infundibulum between the pituitary gland and hypothalamus. Anteriorly it relates to the tuberculum sellae and chiasmatic sulcus, while posteriorly it approaches the dorsum sellae and posterior clinoid processes. Laterally, the dural roof blends with the walls of the cavernous sinuses, placing it immediately medial to the internal carotid artery as it courses through the sinus and to the cranial nerves embedded in the lateral wall. Venous channels and dural sinuses are shown in blue, and the cranial nerves emerging from the brainstem are rendered in yellow, providing orientation to the central skull base. This dural sheet matters because it defines the superior boundary of the hypophyseal fossa and directly influences surgical corridors to sellar and parasellar lesions. In transsphenoidal hypophysectomy for pituitary adenoma, opening the diaphragma sellae risks cerebrospinal fluid leak if the suprasellar cistern is entered, and its configuration helps explain suprasellar extension and optic chiasm compression patterns. The same relationships underpin cavernous sinus invasion, where tumor abuts the carotid artery and the oculomotor, trochlear, and ophthalmic/maxillary divisions of the trigeminal nerve. Neurosurgery and neuroradiology teaching files use this inferior cranial base view to correlate endoscopic endonasal anatomy with MRI of the sellar region (including evaluation of diaphragma sellae incompetence and empty sella). It also fits well in medical school neuroanatomy labs when you want one plate that ties together dura mater reflections, venous sinus anatomy, and cranial nerve exits at the skull base. Anatomical accuracy verified by SciePro's Medical Advisory Board.