Abstract: Objective To find out the relativity between the time when the traumatic prolapse of intervertebral disc occurred and the change of the CT numerical value. Methods The CT numerical value of the vertebral pulp of herniation (denoted as A) and the CT numerical value of the vertebral pulp without herniation (denoted as B) were measured in for 198 patients and analyzed the relation between this parameter and the time when the prolapse of intervertebral disc occurred. Results It′s found find out that there is relativity between the parameter and the time when the prolapse of intervertebral disc occurred,and this difference has the value for the statistics. when the parameter is at about -12 to-40 HU, the average value is-25.8 HU(AB),It can be determined the prolapse of intervertebral disc occurred more than 12 months ago. Conclusion The approximate time can be determined when the prolapse of interverterbral disc occurred by the paremeter.

Key words: clinical forensic medicine, the time of traumatic diskal hernia, the CT numerical value