What is the most inner layer of the meninges known as?

The most inner layer of the meninges is known as the pia mater. The pia mater is a delicate, thin membrane that closely envelops the brain and spinal cord. It is composed of connective tissue and is responsible for providing a supportive environment for the underlying neural tissue. The pia mater contains blood vessels that supply the brain, playing a crucial role in the overall nourishment and protection of the central nervous system.

In contrast, the dura mater is the thick, tough outer layer of the meninges that offers significant protection, while the arachnoid mater acts as the middle layer, lying between the dura and pia mater. Cerebrospinal fluid is a clear fluid that fills the spaces between the pia mater and arachnoid mater, known as the subarachnoid space, providing additional cushioning but is not a layer of the meninges itself. Understanding these distinctions helps clarify the structural hierarchy and functional roles of each component in protecting the brain and spinal cord.