Objective: To analyse and explore the diagnostic significance of infrared thermography on the patients with lumbar intervertebral disc protrusion.Methods: Forty-five hospitalized cases under conservative treatment (mainly manipulation) and 65 controls were consecutively selected. Both groups were examined with infrared thermography on lower back and lower extremities as well as physical examination before and after treatment. The study statistically analysed the temperature difference between the involved and healthy parts at different areas; and also compared the variation of the temperature difference after the treatment to the decreasing scores of physical examination afterward. Results: The statistic result showed that the temperature difference between two sides on patient group was significantly higher than those of the control group. The further analysis showed that the temperature difference at posterior femur area in the patients’ group correlated significantly to the severity of clinical signs caused by nerve root irritation.Conclusion: The thermogram was uncertain to the segmental diagnosis of lumbar disc protrusion and could only be considered as a reference in the final diagnosis. Nevertheless

it is helpful to discover the severity of radical signs according to the posterior femoral region of hypo- (hyper-) thermogram.