The brain has many layers to protect and suspend it in the skull. Under the skull, there is a layer of leathery tissue called the dura mater that encases the brain. Beneath is another layer called the arachnoid mater, named after its spiderweb-like form. Beneath the arachnoid mater is the arachnoid space, a network of proteins that forms a cushion and contains cerebrospinal fluid that suspends the brain in place. Finally, the pia mater wraps closely around all the sulci and gyri of the brain.