Radiographic measurements of the normal spinal cord in childhood.

110 normal air myelograms of children were reviewed and the ratio of the spinal cord width to the subarachnoid space width (cord/SAS ratio) was calculated in the sagittal and transverse planes. This ratio proved to be independent of age and sex. The mean values at different vertebral levels are in close agreement with those previously reported for adults. The cord/sas ratio is helpful in evaluating changed cord dimensions, especially that of cord atrophy.