Stibor’s distance: During this measurement, we connect, in standing position, the spina iliaca dorsalis cranialis on both sides with horizontal line – dermograph. This line intersects L5 spinous process. From this point, we precisely measure the distance to vertebra prominens. In maximal anteflexion of a patient, this distance is elongated by the value called Stibor’s distance. In normal humans, this distance is elongated by 9 cm at 170 cm height. This distance is longer in taller patients and shorter in smaller patients. Distance is longer in young people and shorter in elder ones. If the distance between proximal end of crista sacralis vertebralis (L5) and vertebra prominens is elongated by 9 cm, we say that Stibor’s distance is +9. This distance numerically expresses the range of flexion movement of lumbar and thoracic spine.

Schober’s sign: The line between both spinae iliacae dorsales craniales is marked by a dermograph on the back of patients in standing position. This line intersects L5 spinous process. From this point, we measure, in standing position, 10 cm in proximal direction reaching LI spinous process. In healthy people, processes move away like a fan, the distance between L5 and LI is usually elongated by 5 cm, and this is called Schober’s distance. This distance is significantly reduced in AS patients even in initial stages of the disease. In spondylarthrosis, this distance is elongated less than in healthy people. We designated this sign in abbreviated form as ‘Schober × cm’.

Lateroflexion measurement: The patient puts palms on thighs in standing position, and at the place where tip of middle finger touches the thigh, we will draw the line by dermograph. Then we will ask the patient to make a lateroflexion to the side and to move the hand on lateral part of the thigh to the most distal position. We also have to prevent the patient to simultaneously perform spine rotation in the course of lateroflexion. In maximum lateroflexion, we will mark the place on external lateral side of the leg where the tip of the middle finger can reach. Distance between both lines expresses the numerical motion performed by spine, hip joint and partially arm joint in frontal line. Under normal circumstances, a man can reach the plane, which intersects lower margin of patella with the tip of the middle finger. The distance between both lines should not be smaller than 20 in 170 cm high individual. We designated this sign in abbreviated form as ‘lateroflexion × cm’.

Occiput-wall distance (fleche of J. Forestier). A patient stands towards the wall in such a way so that heels, dorsal part of knees, calves, back and, if possible, the occiput touching it. The patient has to hold their head in such a position so that lateral angle of the eye and upper insertion of the helix would be on the same horizontal straight line. If the patient cannot touch the wall with the occiput, as it usually happens in ankylosing spondylitis, we will measure the horizontal distance between the most dorsal part of occipital bone and wall. This distance is called the occiput-wall distance or fleche. In our case report, we designated this sign as ‘Forestier × cm’.