Thin, delicate membrane that is the middle of the three membranes (meninges) enclosing the brain and spinal cord; the outer membrane is the dura mater, the inner the pia mater.
One of the membranes covering the brain and spinal cord. Arachnoiditis is the name applied to inflammation of this membrane.
The thin, delicate, intermediate membrane of the meninges that encloses the brain and spinal cord. It is separated from the pia mater, the inner membrane, by the subarachnoid space and from the dura mater, the outer membrane, by the subdural space.
The middle membrane among the three that encase the brain and spinal cord.