Membrane organ that surrounds the brain and the spinal cord. [ FMA:9589 ]

This is just here as a test because I lose it

Term information

database cross reference

uberon_slim, efo_slim, pheno_slim, vertebrate_core, organ_slim


Membrane organ that surrounds the brain and the spinal cord.

depicted by


external definition

Membrane covering the brain and spinal cord. It is represented by a single layer in fishes, two in amphibians, reptiles and birds and three in mammals (named dura mater, arachnoid and pia mater). [TFD][VHOG]

external ontology notes

Not consider part of the CNS/neuraxis in FMA

fma set term

has exact synonym

meningeal layer

layer of meninges

has narrow synonym

meninx primitiva

homology notes

In fishes, the meninges consist of a single membrane, the primitive meninx, wrapped around the brain and spinal cord. With the adoption of terrestrial life, the meninges doubled. In amphibians, reptiles, and birds, the meninges include a thick outer dura mater derived from mesoderm and a thin inner secondary meninx. (...) In mammals, the dura mater persists, but division of the secondary meninx yields both the arachnoid and the pia mater from ectomesoderm.[well established][VHOG]



taxon notes

Whereas cyclostomes and fishes only have a single envelope called the primitive meninx, amphibians have two layers, consisting of an outer dura mater which is extremely dense and protective, and a pia-arachnoid or secondary meninx which is more delicate and vascular. Mammals have three meninges: pia mater (which follows all the convolutions of the brain and is the most interior), the arachnoid layer (which is delicate and sends strands to the pia mater), and the dura mater (the outer, more protective meninx).