Brain meninges, historical anatomical artwork. This cranial (top) view of the brain (with front at the top) and its surrounding protective meninges, which have been partially dissected away. The meninges, which cover the brain and spinal cord, consist of three layers: The dura mater (the tough, inflexible outer layer), the arachnoid mater (the delicate middle layer), and the pia mater (the fine, innermost layer). The blood vessels can be seen on the surface of the brain, with arteries red and veins and sinuses blue. This illustration is taken from the 19th century French textbook The Atlas of Human Anatomy and Surgery by J. M. Bourgery and N. H. Jacob.