part of part of subarachnoid space nervous system subarachnoid cistern cistern cisterna UBERON:0004050 BAMS:Ci NCIT:C33640 in FMA is a subdivision of arachnoid space SCTID:314223007 The widening portions of the subarachnoid space within the cranium where the arachnoid bridges over a depression on the surface of the brain. FMA:83717 EMAPA:37813 Wikipedia:Cistern_(neuroanatomy) UMLS:C0228144