Which layer adheres directly to brain and spinal cord surfaces?

• A. Dura mater
• B. Pia mater
• C. Arachnoid mater
• D. Meninges

Answer: (B)

The layer that directly adheres to brain and spinal cord surfaces is the pia mater. It is the delicate, innermost membrane of the meninges and clings tightly to the tissue of the brain and spinal cord, following every contour, groove, and fold. This close contact is what allows it to supply small blood vessels to the neural tissue. The dura mater is the tough outer layer that lines the skull and vertebral canal, providing a strong protective envelope. The arachnoid mater lies between the dura and pia, forming a web-like sheet with a subarachnoid space beneath it that contains cerebrospinal fluid and larger vessels. The term meninges refers to the entire set of these protective coverings.