Difference Between Brain and Spinal Cord Meninges

The key difference between brain and spinal cord meninges is based on the characteristic features of the dura mater. The brain dura mater forms dural folds while the spinal cord dura mater does not form dural folds.

Brain and the spinal cord together form the central nervous system. The meninges refer to the three main layers: dura mater, arachnoid mater and pia mater. Meninges protect both the brain and the spinal cord. Their functions are similar. However, there are minute differences between brain and spinal cord meninges.

CONTENTS

1. Overview and Key Difference
2. What are Brain Meninges
3. What are Spinal Cord Meninges
4. Similarities Between Brain and Spinal Cord Meninges
5. Side by Side Comparison – Brain vs Spinal Cord Meninges in Tabular Form
6. Summary

What are Brain Meninges?

There are three meninges in the brain: dura mater, arachnoid mater, and pia mater. They protect the brain from external shock and maintain the shape of the structures.

The dura mater is the thick and tough outermost layer. One side of the dura mater is attached to the brain. It forms dural folds in the brain. It also helps to retain the cerebrospinal fluid (CSF) in the brain without leaking.

The middle layer is the arachnoid mater. The arachnoid space is not as thick as the dura mater. It takes the structure of a cobweb. It mainly helps in maintaining the structure of the skull. The subarachnoid space between the arachnoid mater and pia mater consists of the cerebrospinal fluid. Thus, it gives rise to the blood-brain barrier by separating the brain from the rest of the organs.

The innermost layer is the pia mater. It is the thinnest layer of all. Moreover, this is a thin membrane that forms around the brain. Thus, it helps in protecting the brain while producing the CSF.

What are Spinal Cord Meninges?

Spinal cord meninges are similar to brain meninges mentioned above. They perform the same functions as summarized below.

• Dura mater – outermost thick layer protecting the spinal cord and retaining the CSF
• Arachnoid mater – middle layer that maintains the structure of the spinal cord and holds the CSF in the subarachnoid space
• Pia mater – innermost layer lining the spinal cord, which produces the CSF

However, there is a structural difference between brain and spinal cord meninges. The principal difference between brain and spinal cord meninges is the presence and absence of the dural folds. The spinal cord dura mater does not form dural folds. Also, there is a space known as the epidural space between the dura mater and the spinal cord, unlike in brain, where there is no space separating the two. And, this space creates an area devoid of the spinal cord. Therefore, it only contains CSF; thus, it’s a good site to extract the CSF.

What are the Similarities Between Brain and Spinal Cord Meninges?

• Both have three meninges: dura mater, arachnoid mater, and pia mater.
• Also, both form the central nervous system.
• The dura mater provides protection to the brain and the spinal cord.
• The arachnoid mater provides structure to the brain and the spinal cord.
• Whereas, the pia mater lines the brain and spinal cord while producing CSF.
• Furthermore, the three layers collectively act to resist external shocks reaching the brain.
• Moreover, it also gives rise to the blood-brain barrier in the spinal cord and the brain.

What is the Difference Between Brain and Spinal Cord Meninges?

The brain and spinal cord meninges are similar in number and function. However, there are minute differences in the dura mater of the spinal cord and the brain. In this context, the dura mater forms dural folds in the brain, whereas it does not form dural folds in the spinal cord. So, this is the key difference between brain and spinal cord meninges.

Moreover, a further difference between brain and spinal cord meninges is that the epidural space is only present in the spinal cord meninges and absent in the brain meninges.

The below infographic summarizes the difference between brain and spinal cord meninges, comprehensively.

Summary – Brain vs Spinal Cord Meninges

The brain and the spinal cord form the central nervous system. The meninges protect both the brain and the spinal cord. There are three meningeal layers: dura mater, arachnoid mater and pia mater. The CSF is present in both, and it acts as the main fluid of the central nervous system. The structural difference of the dura mater creates the difference between brain and spinal cord meninges. That is; the dura mater forms dural folds in the brain, whereas it does not form dural folds in the spinal cord.

Reference:

1. Kenhub. “Meninges of the Brain and Spinal Cord.” Kenhub, Kenhub, 13 June 2019, Available here.
2. “The Spinal Cord.” TeachMeAnatomy, Available here.

Image Courtesy:

1. “Brain and Nearby Structures” By NIH Image Gallery (Public Domain) via Flickr
2. “Gray770-en” By Mysid – Made by Mysid Inkscape, based on plate 770 from Gray’s Anatomy, 1918 (public domain) (Public Domain) via Commons Wikimedia