Diaphragma sellae

The diaphragma sellae is one of the folds (or reflections) of the dura mater. It covers the sella turcica and forms the roof over the pituitary fossa .

Gross anatomy

The diaphragma sellae consists of two horizontal leaves of dura mater on the sphenoid bone. It extends from the tuberculum sellae to the posterior clinoid processes and dorsum sellae and covers the sella turcica and pituitary gland within . It is the medial continuation of the superior roof of the cavernous sinus . It is deficient centrally where the infundibulum of the pituitary gland passes to join the inferior wall of the third ventricle. It does not contain a subarachnoid space.

Relations

• superiorly: optic chiasm
• inferiorly: pituitary gland in the sella turcica, anterior and posterior intercavernous sinuses within the layers of the diaphragma sellae

Variant anatomy

• defects of 5 mm or more in up to 40%  (resulting in empty sella sign)

Radiographic features

CT

• constriction of the diaphragma sellae causing a "snowman appearance" of mass lesions extending into or from the pituitary fossa
• post contrast enhancement is a normal feature

MRI

• more easily appreciable on MRI sequences with long TR or short TE
• enhancement post contrast is a normal feature

Related pathology

• meningioma
• dural metasteses
• normal intracranial calcifications

Siehe auch:

• Sella turcica