Ligament
Diaphragma sellae
Dura between the pituitary and suprasellar region
High-yield
The diaphragm forms an incomplete roof: the stalk must pass through it. Its variable opening helps explain why pituitary masses expand in different directions.
Overview
A dural sheet spans the top of the pituitary fossa to form the diaphragma sellae. The pituitary stalk and associated vessels pass through its opening. The sheet blends with nearby sellar and cavernous-sinus dura, while the optic chiasm occupies the region above it. The size and shape of the opening vary substantially between people.
Reference facts
- Attachments
- Spans the sellar roof between the tuberculum sellae anteriorly and dorsum sellae posteriorly, blending laterally with adjacent dura
- Function
- Separates much of the pituitary fossa from the suprasellar compartment while allowing passage of the stalk and vessels
- Clinical point
- Suprasellar extension may compress crossing optic fibers, producing the classic bitemporal visual-field pattern
Clinical correlation
Upward expansion of a pituitary mass can compress the optic chiasm and impair the temporal visual fields. Lateral invasion can affect cavernous-sinus nerves, causing eye-movement or facial-sensory deficits. Neither growth direction is determined by the diaphragm alone.
Frequently asked questions
Where do the diaphragma sellae attach?
Spans the sellar roof between the tuberculum sellae anteriorly and dorsum sellae posteriorly, blending laterally with adjacent dura.
What do the diaphragma sellae do?
Separates much of the pituitary fossa from the suprasellar compartment while allowing passage of the stalk and vessels.
Why do the diaphragma sellae matter clinically?
Suprasellar extension may compress crossing optic fibers, producing the classic bitemporal visual-field pattern.