The endplate and subchondral bone showed low signal on T1-weighted image and high signal on T2-weighted image, and the histology showed edema, and was associated with increased vascularization of the endplate fissure and subchondral bone marrow, and combined with microfracture phenomenon, named modic type I degeneration; the endplate showed significantly elevated signal on T1-weighted image, while on T2-weighted image it was equal to normal bone marrow signal or mildly elevated, and the histology showed bone marrow fatty degeneration or bone marrow ischemic necrosis, named modic type II. The histological manifestation of this degeneration is histologically modic fatty degeneration or ischemic necrosis of the bone marrow, which is named modic type II. This endplate degeneration usually parallels the edge of the disc and may extend 2 to 10 mm into the vertebral body, sometimes involving up to 50% of the vertebral body. In the sagittal view, it usually extends anteriorly to posteriorly, but rarely involves only the anterior or posterior portion of the vertebral body. On both T1-weighted and T2-weighted images, it appears as a low signal, and the histology shows modic type III degeneration with endplate and subendplate sclerotic bone. The distribution of modic degeneration in age and lumbar segments was observed, and it was found that the degeneration occurred mostly in the age group of 40-80 years, and the highest incidence was observed in L4-5 and L5-S1 modic type 1 modic type 2 modic type 3