Order the meninges from outermost to innermost.

Order the meninges from outermost to innermost.

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

Answer: (A)

The outermost protective covering is the dura mater, a tough, fibrous layer that lines the skull and forms partitions inside the brain. Beneath it lies the arachnoid mater, a thin, web-like membrane that creates the subarachnoid space where cerebrospinal fluid circulates. Closest to the brain is the pia mater, a delicate layer that adheres to the brain’s surface and follows its gyri and sulci, even coating vessels. Therefore, the order from outermost to innermost is dura mater, then arachnoid mater, and finally pia mater. Placing any of the inner layers on the outside would misrepresent the actual anatomical arrangement.

The outermost protective covering is the dura mater, a tough, fibrous layer that lines the skull and forms partitions inside the brain. Beneath it lies the arachnoid mater, a thin, web-like membrane that creates the subarachnoid space where cerebrospinal fluid circulates. Closest to the brain is the pia mater, a delicate layer that adheres to the brain’s surface and follows its gyri and sulci, even coating vessels. Therefore, the order from outermost to innermost is dura mater, then arachnoid mater, and finally pia mater. Placing any of the inner layers on the outside would misrepresent the actual anatomical arrangement.