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Hypophysial cistern

The hypophysial cistern is a cerebrospinal fluid–filled subarachnoid cistern located in the suprasellar region, surrounding the pituitary stalk and inferior aspect of the optic chiasm. It is an important anatomical space that allows passage of critical neurovascular structures between the sellar and suprasellar compartments.

This cistern is a key landmark in neuroanatomy, neuroradiology, and neurosurgery, particularly in the evaluation of the sellar and parasellar regions.

Synonyms

  • Suprasellar cistern (hypophysial component)

  • Chiasmatic–hypophysial cistern

Location

  • Situated above the sella turcica

  • Surrounds the pituitary stalk (infundibulum)

  • Inferior to the optic chiasm

  • Superior to the pituitary gland

  • Anterior to the interpeduncular cistern

  • Continuous with adjacent suprasellar cisterns

Anatomical components

  • Subarachnoid space:

    • Filled with cerebrospinal fluid

  • Cisternal walls:

    • Formed by arachnoid mater reflections

  • Communications:

    • Continuous with the chiasmatic cistern

    • Communicates posteriorly with the interpeduncular cistern

Relations

Superiorly:

  • Optic chiasm

  • Optic nerves

Inferiorly:

  • Pituitary gland

  • Diaphragma sellae

Anteriorly:

  • Tuberculum sellae

  • Chiasmatic cistern

Posteriorly:

  • Interpeduncular cistern

Laterally:

  • Cavernous sinuses

  • Supraclinoid internal carotid arteries

Contents

  • Pituitary stalk (infundibulum)

  • Inferior aspect of the optic chiasm

  • Superior hypophysial arteries

  • Small perforating vessels

  • Cerebrospinal fluid

Function

  • CSF circulation: Allows free flow of cerebrospinal fluid in the suprasellar region

  • Neurovascular accommodation: Provides space for critical structures without compression

  • Anatomical separation: Maintains separation between sellar and suprasellar contents

  • Surgical corridor: Acts as a natural pathway for transcranial and endoscopic approaches

MRI appearance (normal)

T1-weighted images:

  • Cistern: Low signal intensity consistent with CSF

  • Pituitary stalk: Thin, low-to-intermediate signal structure traversing the cistern

T2-weighted images:

  • Cistern: High signal intensity due to CSF

  • Margins: Smooth and well-defined around the pituitary stalk

FLAIR:

  • Cistern: Suppressed (dark) signal

  • CSF spaces: Clearly differentiated from surrounding brain parenchyma

Diffusion-weighted imaging (DWI):

  • Cistern: No diffusion restriction

Post-contrast T1-weighted images:

  • Cistern: No enhancement

CT appearance (normal)

Non-contrast CT:

  • Cistern: Hypodense area consistent with CSF above the sella

Post-contrast CT:

  • Cistern: No enhancement

MRI image

MRI Hypophysial cistern axial anatomy image -img-00000-00000

MRI image

MRI Hypophysial cistern axial anatomy image -img-00000-00000_00001