The meninges refer to the membranous coverings of the brain and spinal cord. There are three layers of meninges, known as the dura mater, arachnoid mater and pia mater.
Based on their location, meninges are referred to as the cranial meninges which envelop the brain, and spinal meninges which envelop the spinal cord. However, the cranial and spinal meninges are continuous with each other and consist of the same three meningeal layers. From superficial to deep the meninges are the:
Meninges of the Brain and Spinal Cord. The pia mater is a thin, highly vascular membrane investing the brain and spinal cord. The arachnoid and pia mater are considered the “soft meninges or leptomeninges (leptomenix)”. The region between the arachnoid and pia mater is the subarachnoid space which is filled with CSF.