composed primarily of leptomeninx pia mater EHDAA:2833 EHDAA:1961 EHDAA:1367 RETIRED_EHDAA2:0001464 SCTID:362305004 NLXANAT:090209 GAID:693 MA:0001116 EMAPA:32663 EHDAA:2001 EHDAA:6566 EHDAA:6583 EHDAA:3692 EHDAA:2867 pia mater of neuraxis EHDAA:2685 Wikipedia:Pia_mater EHDAA:3710 BTO:0001635 MESH:D010841 UBERON:0002361 pial membrane neuronames:1463 The innermost layer of the leptomeninges, consisting of a delicate membrane closely covering the surface of the brain and spinal cord,and lying under the arachnoid membrane. The pia, unlike the arachnoid, extends into the sulci in gyrencephalic animals. NCIT:C33321 FMA:9590 EHDAA:2099 pia EHDAA2:0004318 loose connective tissue