Neuroanatomy, Cranial Meninges

The brain and spinal cord are enveloped within three layers of membrane collectively known as the meninges, with the cranial meninges specifically referring to the section that covers the brain. From superficial to deep, the three layers are the dura, arachnoid, and pia-the term "mater," Latin for mother, often follows these names (i.e., dura mater, arachnoid mater, pia mater).[1] The dura, Latin for "hard," is composed of dense connective tissue and adheres to the inner surface of the skull and vertebrae. The arachnoid is a thin wispy membrane that lies just deep to the dura and is superficial to the pia, the very thin, clear membrane that directly adheres to the surface of the brain and spinal cord. Forming from these layers are three clinically significant spaces, or potential spaces (sometimes called cavities): the epidural, subdural and subarachnoid spaces, from superficial to deep. The chief function of the meninges is to protect the contents of the brain and spinal cord.[2]