Dorsal Arachnoid Web

The arachnoid is a thin transparent membrane that surrounds the brain and spinal cord. A dorsal arachnoid web is an abnormal collection of arachnoid tissue that may compress the spinal cord, usually in the upper thoracic spine producing symptoms of numbness and weakness in the legs. Bowel and bladder function may also be impaired. Microsurgical removal of the abnormal arachnoid tissue is the treatment of choice for this condition.