Which is the outermost layer of the meninges

The pia mater is another thin layer, but unlike the arachnoid it closely follows all of the contours e. Thus, instead of a cobweb, it forms a tight membrane around the brain and spinal cord. The pia acts as a barrier and also aids in the production of CSF. These three layers are similar in structure and function around both the spinal cord and brain, but there are a few differences. While there is not normally a space between the dura and skull, there is one between the dura of the spinal cord and the bone of the vertebral column.

It is known as epidural space , and analgesics and anasthesia are sometimes injected here. Also, the dura of the spinal cord and its accompanying arachnoid layer extend several vertebrae below the end of the cord.

This creates a CSF-filled area called the lumbar cistern where there is no spinal cord present. The lack of the presence of the cord makes the lumbar cistern a good place to sample CSF when necessary because one doesn't have to worry about damaging the spinal cord with a needle puncture. Thus, the lumbar cistern is the site where CSF is aspirated in a lumbar puncture, also known as a spinal tap. There are a number of things that can go wrong with the meninges. Due to the large numbers of blood vessels that travel through these membranes, many problems are vascular in nature.

For example, blood e. Also, the meninges are susceptible to infection, most commonly due to viruses or bacteria. Such an infection can cause meningitis, which is characterized by an inflammation of the meninges. Because of the importance of the meninges in protecting the brain and maintaining normal brain function, meningitis can pose a serious threat to the brain and potentially be life-threatening.

Patel N, Kirmi O. Anatomy and imaging of the normal meninges. PMID: We experience these things every day, but how do our brains create them? Your Brain, Explained is a personal tour around your gray matter. Louis , author, Origins of Neuroscience. Three layers of membranes known as meninges protect the brain and spinal cord. The delicate inner layer is the pia mater.

The middle layer is the arachnoid, a web-like structure filled with fluid that cushions the brain. The tough outer layer is called the dura mater. There is a problem with information submitted for this request. Sign up for free, and stay up-to-date on research advancements, health tips and current health topics, like COVID, plus expert advice on managing your health.

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