Firstly, we recruit nurses with low back pain in one group, with the normal as control. Then the subject will accept 3.0T MRI scanning at the same time. Before scanning we will determine the MRI sequence to make sure the imageis are clear enough. At last, we will analysis the photos in the image processing workstation, reconstruct the anatomical structure in the scanning area. All of this is to find a possible reason or explanation in the occurrence of incipient lumbago through the comparison of two group`s images.