The key difference between cranial dura and spinal dura is that cranial dura is the outer meninges that cover the brain, while spinal dura is the outer meninges that cover the spinal cord.
The brain and spinal cord are protected by three layers of membranes called the meninges. The three types of meninges are the dura mater, arachnoid membrane, and pia mater. The dura mater is the outermost layer, the arachnoid membrane is the middle layer, and the pia mater is the innermost layer. With reference to the site, there are two types of dura mater: cranial dura, which covers the brain, and spinal dura, which covers the spinal cord.
CONTENTS
1. Overview and Key Difference
2. What is Cranial Dura
3. What is Spinal Dura
4. Similarities – Cranial Dura and Spinal Dura
5. Cranial Dura vs Spinal Dura in Tabular Form
6. Summary – Cranial Dura vs Spinal Dura
What is Cranial Dura?
The cranial dura mater is the outer meningeal layer. It consists of irregular connective tissues and is composed of two layers. The superficial layer is the periosteal cranial dura, and the other layer is the meningeal dura. The periosteal dura is attached closely to the internal surface of the skull bones. This layer provides a tubular covering for the cranial nerves when they pass through the different foramina of the skull. After the exit of the cranial nerves from the foramen, the periosteal layer fuses with the epineurium of nerves. The meningeal dura is continuous with the spinal dura that lies superficial to the arachnoid mater. It is a dense fibrous membrane that passes through the foramen magnum. The periosteal dura and meningeal dura are tightly fixed together except where they separate to enclose the dural venous sinuses. The meningeal layer makes several dural folds, which divide the cranial cavity.
The function of the cranial dura folds is to limit the rotational displacement of the brain. The folds include falx cerebri, falx cerebelli, tentorium cerebelli, and diaphragm sellae.
What is Spinal Dura?
Spinal dura is the outermost layer of the tissue that surrounds the spinal cord. The spinal dura consists of two layers: endosteal layer and meningeal layer. It primarily consists of a fibrous and non-adherent layer, which comes from the outermost layer of the meninges. The fibrous and elastic bands run parallel to each other, and they are internally covered by the mesothelium.
The blood supply to the spinal dura originates from the anterior and posterior radicular arteries. The main function of the spinal dura is to encase the spinal cord along its length and to partition the central and peripheral nervous systems. Moreover, the termination point of the spinal dura is at the level of the second sacral vertebra. Damage to the dura mater occurs mostly during traumatic incidents to the spinal cord during accidents, surgical procedures, meningeal diseases, and lumbar functions. These damages will not heal by themselves and would require extensive surgical procedures.
What are the Similarities Between Cranial Dura and Spinal Dura?
- The cranial dura and spinal dura are meninges.
- Both consist of dura mater.
- They are involved in providing protection.
- They are prone to traumatic damage more often.
- Both types are the outermost covering layer of the respective site.
What is the Difference Between Cranial Dura and Spinal Dura?
The cranial dura is the outer meninges that cover the brain, while the spinal dura is the outer meninges that cover the spinal cord. Thus, this is the key difference between cranial dura and spinal dura. Besides, the cranial dura consists of epidural space and folds and reflections, while the spinal dura does not. Moreover, the function of the cranial dura is to protect the brain, whereas the function of the spinal dura is to protect the spinal cord.
The below infographic presents the differences between cranial dura and spinal dura in tabular form for side-by-side comparison.
Summary – Cranial Dura vs Spinal Dura
The brain and spinal cord are protected by three layers of membranes called the meninges. The three types of meninges are dura mater, arachnoid membrane, and pia mater. The dura mater is the outermost layer. Of this, the cranial dura is the outer meninges that cover the brain, while the spinal dura is the outer meninges that cover the spinal cord. Furthermore, the cranial dura protects the brain, while the spinal dura protects the spinal cord. So, this summarizes the difference between cranial dura and spinal dura.
Reference:
1. “Dura Mater – An Overview.” ScienceDirect Topics.
2. Hacking, Craig. “Spinal Dura Mater: Radiology Reference Article.” Radiopaedia Blog RSS.
3. MD, Jana Vasković “Meninges of the Brain and Spinal Cord.” Kenhub.
Image Courtesy:
1. “1315 Brain Sinuses” By OpenStax – (CC BY 4.0) via Commons Wikimedia
2. “Spinal dura mater 3” By Anatomist90 – Own work (CC BY-SA 3.0) via Commons Wikimedia