MR Imaging Determination of the Location of the Normal Conus Medullaris Throughout Childhood

Abstract

This retrospective study was designed to determine the location of the conus medullaris in normal children by reviewing a series of MR images of the lumbar spine. The study group consisted of 184 children ranging in age from newborn to 20 years who had a normal conus level as reported by the radiologist of record. The range of conus levels for the entire group of normal children was T12 to L3. The range for the 0-2-year-old group was T12 to L2-L3 with an average of L1-L2. The range of conus levels for the 19-20-year-old group was L1 to L2 with an average of L1-L2.

We conclude that the conus medullaris does not ascend throughout childhood as stated by previous authors but attains the adult level sometime during the first few months of life. A conus level at L2-L3 or above should be considered normal at any age. A conus level at L3 is indeterminate, since it is possible for a normal or a tethered conus to be located at this level.