Meninges - The protective covering

The meninges are three specialized connective tissue membranes that surround and protect the brain and spinal cord, providing both structural support and a protective barrier against injury and infection. From outermost to innermost, they consist of the dura mater, a tough fibrous layer firmly attached to the skull; the arachnoid mater, a delicate, web-like membrane beneath which lies the subarachnoid space filled with cerebrospinal fluid (CSF) that cushions the brain; and the pia mater, a thin, highly vascular membrane that closely follows every fold and groove of the brain, supplying nutrients to the nervous tissue. The meninges also contain dural venous sinuses, which drain deoxygenated blood from the brain and provide pathways for blood vessels and cranial nerves. Inflammation of these membranes causes meningitis.