While the patient is in a standing position the examiner makes a mark approximately at the level of L5 (fifth lumbar vertebra). Two points are marked: 5 cm below and 10 cm above this point (for a total of 15 cm distance). Then the patient is asked to touch his/her toes while keeping the knees straight. If the distance of the two points do not increase by at least 5 cm (with the total distance greater than 20 cm), then this is a sign of restriction in the lumbar flexion.  This can be useful in examining a patient suspected of ankylosing spondylitis.