Human Meninges: Anatomy and Its Role in Meningioma Pathogenesis

In this chapter the functional anatomy of human meninges is described, with particular attention paid to the pathological aspects. The meninges, the intricate and complex coverings of the brain and spinal cord, are basically comprised of three distinct yet closely associated layers: dura mater, arachnoid, and pia mater. Dura mater is thick, while the arachnoid is thin, and the subarachnoid space is of varying thickness. Dura mater is comprised of periosteal dura, meningeal dura, and dural border layer. The arachnoid is comprised of an arachnoid barrier layer and arachnoid trabeculae. For the thorough understanding of the meninges and related structures, not only gross but also light and electron microscopic observations and molecular analyses are indispensable. However, from postmortem analyses it is not possible to determine in situ features of the meninges in the living individual. Meninges are essentially composed of a series of fibroblasts and/or arachnoid cells, as well as varying amounts of extracellular materials, fibers, and fluid-filled cisterns. Usually considered as a simple protective covering, the meninges are closely related to both physiology and pathology of the central nervous system. Dura mater is a rigid but simple covering of the brain as an internal covering of calvaria. Dura mater forms venous sinuses that drain not only blood but also the cerebro-spinal fluid (CSF).