The meninges are three protective membranes—dura mater, arachnoid mater, and pia mater—that envelop the brain and spinal cord. Their primary function is to provide a barrier against mechanical injury and to contain cerebrospinal fluid, which cushions the CNS. In surgical procedures, careful dissection of the meninges is critical to avoid damage to underlying neural tissues and prevent infections such as meningitis. The dura mater is particularly important as it forms a tough outer layer that surgeons must incise to access the brain or spinal cord safely.

Reference: Gray's Anatomy, Susan Standring, 42nd Edition.