A meningocele is defined in Dorland's Medical Dictionary as a hernial protrusion of the meninges through a defect in the skull or vertebral column (2). According to this definition, an expansion of the subarachnoid space within the spinal canal does not constitute a meningocele. “Intraspinal meningocele” (2) and “occult meningocele” (:3) exist in the literature as misnomers lacking the essential element of a meningocele—a hernial protrusion through a bony defect. It is the purpose of this communication to present 4 cases illustrating the expansion of the subarachnoid space within the spinal canal and to attempt to clarify the apparent confusion surrounding this condition. Case Reports Case I: A 46-year-old female with multiple neurofibromatosis was first seen at the University of Kentucky Medical Center in June 1965 with the complaint of bilateral posterior thigh and calf pain. The pain was made worse by turning and twisting and relieved by recumbency. She had occasional lower-lumbar back pain exacerbated...