Understanding the anatomy can lead to prompt identification of serious pathology
The meninges are three membranous layers that surround the structures of the central nervous system. They include the dura mater, the arachnoid mater, and the pia mater. Together they cushion the brain and spinal cord with cerebrospinal fluid and support the associated vascular structures.12 Although they are usually mentioned as a trio, there are subtle but important differences to the arrangement of the meninges in the spine and cranium. The aim of this introduction to the meninges is to clarify the anatomy and link these details to relevant clinical situations.
The outermost of the meninges (singular: meninx) is the dura mater, commonly called the dura.3 As its name suggests, the dura is a tough thick membrane composed of dense collagen fibres.234
In the cranium, the dura is continuous with the periosteum of the inner surface of the skull and extends into folds that compartmentalise the skull.12 The large midline fold