The subarachnoid cisterns, or basal cisterns, are compartments within the subarachnoid space where the pia mater and arachnoid membrane are not in close approximation and cerebrospinal fluid (CSF) forms pools or cisterns (Latin: "box"). As they are interconnected, their patency is essential for CSF circulation. Cisterns may have vessels and/or cranial nerves passing through them.

The named subarachnoid cisterns are (roughly from superior to inferior):

• pericallosal cistern (unpaired): superior to the cistern of the lamina terminalis, superior to the corpus callosum 

• cistern of the lamina terminalis (unpaired): superior to the suprasellar cistern, anterior to the anterior wall of the third ventricle

• Sylvian cistern (paired): deep part of the Sylvian fissure

• cistern of the velum interpositum (unpaired): between the layers of tela choroidea in the roof of the third ventricle

• suprasellar (chiasmatic) cistern (unpaired): ​anterior to the interpeduncular cistern, surrounds the pituitary infundibulum and optic chiasm

• carotid cistern (paired): lateral to the suprasellar cistern, surrounds the supraclinoid internal carotid artery

• perimesencephalic cisterns

  • interpeduncular cistern (unpaired): between the cerebral crura

  • crural cisterns (paired): between the cerebral crus and uncus of the temporal lobe

  • ambient cisterns (paired): posterolateral to the midbrain

  • quadrigeminal cistern (unpaired): between colliculi, splenium of the corpus callosum, and superior surface of the cerebellum

• superior cerebellar cistern (unpaired): posterior to the quadrigeminal cistern, between the superior surface of cerebellum and tentorium

• prepontine cistern (unpaired): anterior to the pons

• cerebellopontine (cerebellopontine angle) cisterns (paired): lateral to the pons, at the cerebellopontine angle

• cerebellomedullary (lateral cerebellomedullary) cisterns (paired): lateral to the medulla oblongata

• premedullary cistern (unpaired): anterior to the medulla

• cisterna magna (unpaired): posterior to the medulla, the largest of the subarachnoid cisterns

The cisterns are, in some instances, separated from each other by arachnoid membranes. 

Related pathology

• mass effect and increased intracranial pressure, effacing one or more of the cisterns

• subarachnoid haemorrhage, including perimesencephalic subarachnoid haemorrhage, filling one or more of the cisterns with blood

• arachnoid cyst