Spondylosis diffusely affects the vertebral column but is more pronounced in the cervical and lumbar regions where mobility is greatest. Of 214 patients treated for symptomatic spinal spondylosis, 63 patients (29%) were found to have symptoms related to the cervical spine alone: 123 (58%) had symptoms relative to the lumbar spine alone; 28 (13%) were found to have symptoms relative to both the cervical and lumbar spine in a retrospective clinical study. The incidence of occurrence of a narrow spinal canal was determined. In the patients with cervical spondylosis alone, 40 patients (64%) were found to have midcervical sagittal diameters below average. Eighty-seven patients (71%) with lumbar spondylosis had spinal canals below the average measurements. In the group of patients with combined disease of the cervical and lumbar spine, 18 of the 28 patients (64%) had spinal canal diameters below the accepted average values.