Posterior perforated substance

The posterior perforated substance is located in the depressed area between the cerebral crura (termed interpeduncular fossa), and consists of a layer of gray matter which is pierced by small striate vessels (including branches of cerebral posterior artery: posteromedial central arteries and thalamoperforating arteries). These originate from the circle of Willis and navigate through the posterior perforating substance to penetrate deeper into the brain tissues. This arrangement supplies blood supply to vital subcortical brain regions, including the basal ganglia, internal capsule, and thalamus.

The lower part of the posterior perforated substance lies on the ventral aspect of the medial portions of the tegmenta, and contains the interpeduncular nucleus.

Its upper part assists in forming the floor of the third ventricle.