Which layer of the meninges adheres directly to CNS tissue?

The pia mater is the layer of the meninges that is directly attached to the central nervous system (CNS) tissue. This innermost layer is extremely thin and delicate, following the contours of the brain and spinal cord closely. It plays a crucial role in providing a protective barrier for the nervous tissue while also allowing for the exchange of nutrients and waste.

The other layers of the meninges—the arachnoid mater and the dura mater—are positioned above the pia mater and do not come into direct contact with the CNS tissue. The arachnoid mater sits atop the pia mater and is separated from it by the subarachnoid space, which contains cerebrospinal fluid. The dura mater is the outermost layer, providing additional protection, but it is also not in direct contact with the CNS. The subdural space is the potential space between the dura mater and the arachnoid mater, further illustrating the separation between these layers.