To ensure adequate use of the technique of computed myelography (CM) it is necessary to have an exact picture of the morphology of the normal spinal cord as demonstrated by this technique. This has been obtained by studying the morphology and measuring the frontal and sagittal diameter of the cervical cord in 20 patients. The normal values are presented. The changes of this morphology in one patient with a tumour, one patient with atrophy of the spinal cord and in some patients with congenital malformations are also reported.