In the midline from the anterior superior part of the chiasmatic cistern, a channel extends to the cistern of the lamina terminalis. Immediately anterior to the lamina terminalis, this cistern continues into the cistern of the corpus callosum, which lies on top of the corpus callosum between the cerebral hemispheres.
The cistern of the corpus callosum joins the lateral cerebrocortical subarachnoid channels and the ambient cistern below the splenium of the corpus callosum. The cisterna ambiens (ambient cistern, superior cistern, or cistern of great cerebral vein) surrounds the posterior, superior, and lateral surfaces of the midbrain, is related to the inferior surface of the tentorium cerebelli, and contains the great vein of Galen, the posterior cerebral arteries, and the superior cerebellar arteries. In some individuals, there may be a cerebrospinal-fluid-containing space between the layers of the velum interpositum forming the cistern of the velum interpositum (cistern of the great transverse cerebral fissure).