The paper deals with a rare case of fracture of the lumbar vertebra in psoriatic arthropathy which finally led in a 39-year old female patient with a 14-year-old history of the disease to straightening of the spine. The fracture of the vertebral body L2 with straightening of the lumbar section by 25 degrees healed after conservative treatment without any complications. The case is discussed from the aspect of the cause of the fracture, mechanism of the episode. The resulting position of the spine is compared with the results of surgery, i. e. rachotomy. Key words: psoriatic spondylarthropathy, pathological fracture of the lumbar vertebra, rachotomy.