An Overview of Arachnoid Webs

Arachnoid webs are abnormal formations of arachnoid membrane in the spinal subarachnoid space that prevents movement of cerebrospinal fluid (CSF) in the longitudinal direction1.These webs represent intradural extramedullary transverse bands of arachnoid tissue that extend to the dorsal surface of the spinal cord resulting in dorsal indentation2. These arachnoid webs may represent a variant of an arachnoid cyst3. However, they may also represent localized arachnoiditis3.