The pia mater at the site of the entry of blood vessels into the central nervous system.
D000818:Animals; D001933:Brain Stem / Q000098:blood supply*; D002415:Cats; D008855:Microscopy, Electron, Scanning; D010841:Pia Mater / Q000098:blood supply*; D011817:Rabbits; D013116:Spinal Cord / Q000098:blood supply*; D013346:Subarachnoid Space