Meninges

Definition

The meninges are a trio of protective membranes that encase the brain and spinal cord. They consist of three layers: dura mater, arachnoid mater, and pia mater.

5 Must Know Facts For Your Next Test

1. The dura mater is the outermost layer and provides the most protection.
2. The arachnoid mater is the middle layer and is involved in cushioning the central nervous system.
3. The pia mater is the innermost layer that closely adheres to the surface of the brain and spinal cord.
4. Cerebrospinal fluid circulates within the subarachnoid space between the arachnoid mater and pia mater.
5. Meningitis is an inflammation of the meninges usually caused by infection.

Review Questions

• What are the three layers of the meninges?
• Which meningeal layer is directly attached to the brain?
• Where does cerebrospinal fluid circulate within the meninges?

Related terms

Dura Mater: The tough, outermost membrane surrounding and protecting the brain and spinal cord.

Arachnoid Mater: The web-like middle layer of meninges that cushions the central nervous system.

Pia Mater: The delicate innermost membrane that clings tightly to the brain and spinal cord.