58 - Basal cistern

The interpeduncular cistern (basal cistern or Fossa interpeduncularis) is a wide cavity where the arachnoid extends across between the two temporal lobes.

It encloses the cerebral peduncles and the structures contained in the interpeduncular fossa, and contains the arterial circle of Willis.

Diagram showing the positions of the three principal subarachnoid cisternæ. Interpeduncular cistern labeled at left center.