The tough fibrous outermost covering of the spinal cord is the:

• A. arachnoid mater
• B. epineurium
• C. dura mater
• D. pia mater

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the anatomy of the spinal cord and its protective layers. The spinal cord is surrounded by three meninges: dura mater, arachnoid mater, and pia mater, which provide protection and support.
2. Step 2: Learn the characteristics of each meningeal layer. The dura mater is the tough, fibrous outermost layer; the arachnoid mater is the middle layer with a web-like structure; and the pia mater is the innermost layer that adheres closely to the spinal cord.
3. Step 3: Compare the options provided in the question. The arachnoid mater is not the outermost layer, but the middle layer. The epineurium is a connective tissue layer surrounding peripheral nerves, not part of the meninges. The pia mater is the innermost layer, not the outermost.
4. Step 4: Identify the correct answer based on the description of the dura mater as the tough, fibrous outermost covering of the spinal cord.
5. Step 5: Confirm your understanding by reviewing the structure and function of the meninges in protecting the central nervous system.