GLOSSARY

The meninges are three layers of protective membrane covering the brain and spinal cord, protecting them from impact, containing the cerebrospinal fluid, and supporting the blood vessels.

Layers (Outside to Inside)

• Dura mater: thick, tough, and fibrous, attached to the skull; the brain’s venous sinuses lie within it.
• Arachnoid mater: a thin, web-like middle layer.
• Pia mater: very thin, adhering closely to the surface of the brain and spinal cord and following its grooves.

Important Spaces

• Epidural space: between the skull and the dura (in the spine, a real space containing fat, the site of epidural anaesthesia).
• Subdural space: between the dura and the arachnoid.
• Subarachnoid space: between the arachnoid and the pia, containing cerebrospinal fluid and the brain’s major arteries.

Clinical Application