[Manual examination of so-called lumbosacral instability]

By the manual test of the lumbosacral instability described by Eder and Tilscher we can never find out for certain whether the fifth lumbar vertebra can be shifted ventrally above the sacrum. Before this test the patient has to be turned over on to his side with hips flexed, which causes a ventral flexion (anteflexion) of the lumbosacral segment. During the test, however, the lumbosacral segment is forced to a dorsal flexion (retroflexion); therefore the spinous process of the fifth lumbar vertebra retires from the back surface simulating a sliding forward of the whole vertebra.