Abstract: Abstract Objective：infrared thermal Imaging Technique for examination of block height methods to measure the spinal bolck height with infrared thermography before and after spinal anesthesia in 24 cases perfomed the operations of lower abdomen or lower extremities and to analyze the images qualitatively.The changes in thermal lvevels are analyzed and compared to those with the sensory testing with skin prodding.Results:the levels obtained with infrared imaging technique are higher than thoes with skin prodding testing the levels of sensory analgesia ara fixed between T9 to S11. while the thermal levels are between T12 to S5,the difference is 2 spinal cord segments.After the nerves in subarachnoiol space are blocked the color coded thermal zones in infrared images especially the areas innervated by L5~S1,chage respectively.Conclusion:Infrared thermal imaging can be used to measure the spinal anesthetic block levels indirectly,and has some clinical application value.

Key words: Infrared Thermal Imaging, Measure, Spinal anesthetic block, Levels