(n) a congenital anomaly of the central nervous system in which a sac protruding from the brain or the spinal meninges contains cerebrospinal fluid (but no nerve tissue)
(n) a congenital defect of the central nervous system in which a sac containing part of the spinal cord and its meninges protrude through a gap in the vertebral column; frequently accompanied by hydrocephalus and mental retardation
The Collaborative International Dictionary of English (GCIDE) v.0.53 Collaborative International Dictionary (GCIDE)