[Differentiation of spondylitis ankylopoietica and spondylitis hyperostotica]

Changes in the bodies of vertebrae in ancylopoetic spondylitis (Bekhterev's disease) and in hyperostotic spondylitis (Forestier's disease) may be very similar, in particular as regards the ancylotic connection of the bodies of the vertebrae and syndesmophytes. In the differential diagnosis the following differences are important: Syndesmophytes in Bekhterev's disease are symetrical and continuous, there is ossification of the intervertebral discs, and ancylosis affects always sacroiliac, intervertebral and costovertebral joints. In hyperostotic spondylosis the sclerotic syndesmophytes bulge in a lateral direction, mainly to the right. The inveretebral discs do not ossify, the sacroilliac and other above mentioned joints are not affected.