Your meninges play an important function in your body as part of the brain and spinal cord. What are the meninges? Read on to learn what they do, signs of meninges-related conditions, and more.
What Are Meninges?
There are three meninges layers that completely envelop your brain and spinal cord, which make up your central nervous system. These layers are the dura mater, arachnoid mater, and pia mater. Together, your meninges stabilize your brain, protect sensitive areas, and give support to nerves, blood vessels, lymphatics, and the cerebrospinal fluid found in your central nervous system.
The dura mater is the outermost layer and is closest to the skull. It contains the periosteal layer and the meningeal layer. The arachnoid mater is in between the dura and pia mater. The pia mater is the innermost layer and is closest to the brain tissue. The arachnoid and pia mater can be grouped together and are called the leptomeninges.
The characteristics of each meninge are as follows:
- Dura mater. This meninge is very strong and thick, and it forms a bridge between the skull and arachnoid mater. It contains a drainage system known as the dural venous sinuses, which carry blood away from your brain and circulate cerebrospinal fluid. Blood comes to the dura mater by way of the middle meningeal artery and vein. The dura mater has a series of dural reflections, thin layers of membrane made of folded dura mater, located in different parts of your brain.
- Arachnoid mater. This is a much thinner layer that doesn’t have any nerves or blood vessels. Like its name implies, it looks similar to a spiderweb due to connective tissue that hooks it up to the pia mater.
- Pia mater. This is also a thin layer stretched tightly across the brain and spinal cord like plastic wrap. Blood vessels have to make their way through the pia mater to bring blood to your brain tissue. The pia mater holds cerebrospinal fluid and helps keep your spinal cord stiff.
There are meninges spaces between each layer:
- Epidural space. This is located in between the skull and dura mater and between the spinal cord’s dura mater and the bones in the vertebral column. It’s common to insert pain medicine and anesthesia into this space via injection. A doctor can perform a spinal tap, or lumbar puncture, in the epidural space between the first two lumbar vertebrae in the middle of the back where the spinal cord ends.
- Subdural space. This is located between the dura and arachnoid mater. The name is a little misleading, as there isn’t normally a space here, but if you have a brain bleed, brain trauma, or other medical condition, a space will appear here.
- Subarachnoid space. This is located between the arachnoid and pia mater. It’s full of cerebrospinal fluid to provide extra protection for your brain and spinal cord.
What Do Meninges Do?
Your meninges have two main functions: protecting and supporting. They prevent trauma injuries to the central nervous system by absorbing shock, and they act as an anchor for the central nervous system that stops your brain from jostling around inside your skull.
The meninges also support the activities of other parts of your body, like your blood vessels, lymphatics, cerebrospinal fluid, and nerves.
Where Are Meninges Located?
The meninges and spaces are located in the following places, from top to bottom:
- The epidural space is located between the top of the skull and the top of the dura mater.
- The dura mater is the topmost layer, located by the top of the skull and the brain tissue, on top of the subdural space.
- The subdural space, when it exists, is in between the dura and arachnoid mater.
- The arachnoid mater is in between the dura and pia mater.
- The subarachnoid space is in between the arachnoid and pia mater.
- The pia mater is the deepest layer, underneath the arachnoid mater.
Signs Something Could Be Wrong With Your Meninges
Depending on what's wrong with your meninges, your signs and symptoms will vary. Symptoms of meningitis, one of the most common meningeal conditions, include:
- Unexpected high fever
- A stiff neck
- Intense headaches that feel different from your typical headaches
- Vomiting or intense nausea
- Inability to concentrate
- Feeling confused
- Feeling lethargic
- Difficulty waking up
- Light sensitivity
- Low appetite or thirst
- Topical rash
What Conditions Affect Meninges?
There are a number of conditions that can affect your meninges. Your meninges are important for keeping your brain safe, so conditions that affect them could be life-threatening. The most common ones are meningitis, subdural hematomas, and bleeding in the meninges:
- Meningitis is an infection in your meninges due to a virus, fungus, or bacteria. On rare occasions, it can also be caused by cancer, brain surgery, or some kinds of medication. To diagnose meningitis, your health care provider will need to take a sample of your cerebrospinal fluid.
- Subdural hematomas consist of bleeding in between the dura and arachnoid mater due to a torn blood vessel.
- Other kinds of bleeding in your meningeal layers can happen simply because of how many blood vessels pass through the meninges. Head trauma or similar injuries can result in bleeding in between any meningeal layers, especially if you have a bleeding disorder or take blood thinners.
How Can You Keep Your Meninges Healthy?
There are a few things you can do to keep your brain and spine healthy. The most important step you can take is to have a balanced diet. Did you know that the brain uses 20% of the energy your body makes, but it only makes up 2% of its weight? This means that if you’re not fueling your body well, your chances of mental and physical fatigue, memory issues, and difficulty concentrating greatly increase. Including the following in what you eat can improve your brain and heart function and decrease your risk of many serious illnesses:
- Complex carbohydrates
- Fatty acids
- Amino acids
- Vitamins and minerals
- Foods found in a Mediterranean diet
- Extra virgin olive oil
- Oily fish
- Deep-colored vegetables and fruits
- “Good” fats
- Dark chocolate
- Green tea
Avoid salty foods, sugary food and drinks, trans fats, alcohol, and other foods that don’t make you feel your best. On top of all of this, make sure you’re exercising, getting enough sleep, and stimulating your brain. If you think you have a meningeal or other brain-related condition, reach out to your health care provider immediately.