part of part of location of adjacent to anatomical space cerebrospinal fluid blood vessel pia mater meningeal cluster perivascular space perivascular region The space between a blood vessel and the pia mater. VRS belonging to the subarachnoid space are continuous with VRS of the subpial space. The direct communication between VRS of the subarachnoid space and the subpial space is unique to the brain's arteries, as no leptomeningeal layers surround the brain's veins[WP] SCTID:342298001 Wikipedia:Virchow-Robin_space UMLS:C0225983 perivascular spaces UBERON:0014930 VRS NCIT:C83196 Virchow-Robin space