What is the Difference Between Dura Mater and Pia Mater

The main difference between dura mater and pia mater is that the dura mater is the outer layer of the meninges that is closest to the skull, whereas the pia mater is the inner layer of the meninges that is closest to the brain.

Dura mater and pia mater are meningeal layers covering and protecting the brain and spinal cord. 

Key Areas Covered

1. What is Dura Mater
– Definition, Features, Importance
2. What is Pia Mater
– Definition, Features, Importance
3. Similarities Between Dura Mater and Pia Mater
– Outline of Common Features
4. Difference Between Dura Mater and Pia Mater
– Comparison of Key Differences

Key Terms  

Dura Mater, Pia Mater

What is Dura Mater

The dura mater is a layer of connective tissue that makes up the meninges of the brain. Merely the dura is another name for the dura mater. Importantly, it is the outermost layer of the three meninges. Therefore, it surrounds and protects the brain and the spinal cord. Also, fibroblasts and a large amount of extracellular collagen make up the dura mater. The periosteal/endosteal layer and the meningeal layer are the two layers of the dura mater. Also, the septa of the dura folds form falx cerebri, tentorium cerebelli, falx cerebelli, and diaphragma sellae.

Figure 1: Dura Mater

Furthermore, the periosteal or endosteal layer is a peristomium layer covering the skull’s inner surface. It forms a tubular sheath-like covering around the cranial nerves. The periosteal layer fuses with the epineurium of nerves as soon as the cranial nerves exit the foramen. However, it does not occur in the dura mater of the spinal cord. Further, the meningeal layer is durable and made up of a dense fibrous membrane. By contrast, it continues with the spinal cord. Also, the epidural and subdural spaces are the two potential spaces that can occur in the dura matter. The epidural space occurs between the dura mater and the skull. In contrast, subdural space occurs in the subdural compartment between neurothelial cells.

What is Pia Mater

The Pia mater is the innermost layer of the meninges surrounding the central nervous system. It is a thin, transparent layer. Leptomeninges is the collective name for pia and arachnoid layers. The arachnoid layer is the third meningeal layer. An important feature of pia matter is that it is highly vascularized. It contains fine blood vessels. Pial coats are the extensions of the pia mater. The extensions of the spinal cord are similar to the extensions of the pia mater. The pial coat covers the spinal nerves and blood vessels that travel away from the central nervous system.

Figure 2: Pia Mater 

Moreover, the pia mater forms a tiny ligament called the denticulate ligament. It suspends within the dural sac.  

Similarities Between Dura Mater and Pia Mater

• Dura mater and pia mater are two layers of meninges.
• They protect the brain and the spinal cord.
• Also, they act as shock absorbers.
• They support blood vessels. 

Difference Between Dura Mater and Pia Mater

Definition

Dura mater is the tough outermost membrane enveloping the brain and spinal cord. In contrast, the pia mater is the thin vascular membrane that invests the brain and spinal cord internal to the arachnoid and dura mater.

Location

Dura mater is the outer layer of the meninges that is closest to the skull, while the pia mater is the inner layer of the meninges that is closest to the brain.

Function

Dura matter limits the rotational displacement of the brain, while pia matter helps contain cerebrospinal fluid.

Conclusion

In brief, the dura and pia mater are two meningeal layers in the brain. The Dura mater is the outer layer of the meninges. It occurs closest to the skull. Its function is to limit the rotational displacement of the brain. In comparison, the pia mater is the inner layer of the meninges. However, it occurs closest to the brain. It helps to contain cerebrospinal fluid. Therefore, the main difference between dura and pia mater is their location and function.

References:

1. Kekere V, Alsayouri K. Anatomy, Head and Neck, Dura Mater. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.
2. MSc, N. M. (2023, August 23). Pia Mater. Kenhub. 

Image Courtesy:

1. “Meninges-en” By Mysid – Own Work (CC-BY SA 3.0) via Commons Wikimedia
2. “Gray770-en” By Mysid – Own work (Public Domain) via Commons Wikimedia