The cervical spinal canal at C_3-C_7 (200 in total) of 40 adult cervical spinal columns were measured on the axis radiograph. The diameter and area of spinal canal and corresponding spinal cord were investigated with vernier calipers and planimeter.The average values of the measurements are reported as follows:1. The sagittal and transverse diameter of the cervical spinal canal at C_3-C_7 are 13.71?1.31mm and 24.15?1.91mm, while those of the corresponding segment of spinal cord are 7.99?1.01mm and 13.35?1.64mm, respectively.2. The total area of the spinal canal and spinal cord at C_3-C_7 are 239.35?41.78 mm~1 and 106.6?9.9 mm~2, respectively. These data were studied with computer using multiple linear regression analysis program and a calculating formula of cervical spinal canal and the corresponding segment of spinal cord were inferred.Since sagittal and transverse diameters of vertebral canal and cervical spinal cord are measured, we may calculate the both area by using above mentioned formula. This will offer a new method for diagnosis of spinal canal stenosis and spondylosis.