The meninges are a three-part sheath of membranes that, along with the cerebrospinal fluid, cover and protect the central nervous system. The Neurological Relief Centers have developed a system of therapy based on the idea that compression of the meninges - Meningeal Compression - explains fibromyalgia and a myriad of neurologic diseases and conditions.
The outermost part, closest to the skull, is a thick, durable membrane called the dura mater. Its two layers form the outermost meningeal sac that covers the inner membranes and supports the larger blood vessels that carry blood from the brain back to the heart. The dura mater is attached to the skull and the bones that form the vertebral canal.
The middle membrane is called the arachnoid because of its spider-web structure. It serves to cushion the central nervous system.
The innermost membrane is the pia mater, a very thin, delicate envelope that is firmly attached to the surface of the brain and spinal cord. The space between the arachnoid and pia mater is filled with cerebrospinal fluid.