Modified Schober test

This test measures lumbar flexion and is used to diagnose ankylosing spondylitis. Have the patient stand upright and place marks at the level of the sacral dimples on both sides (the lumbosacral junction). A horizontal line is drawn connecting these 2 points (iliac crest line). Marks are then placed midline (over the spine) 5 cm below and 10 cm above the ileac crest line. Have the patient bend forward as far as possible without bending at the knees (maximum lumbar flexion) and measure the distance between the top and bottom point. The distance between these 2 marks should increase from 15 cm standing to at least 20 cm with maximum flexion. A distance <20 cm is abnormal.