Kinematics of the lumbar spine : clinical significance of lateral X-rays of the lumbar spine in anteflexion and retroflexion in healthy individuals, in cases of symptomatic herniated lumbar disc diseases and of spondylolisthesis

About half of the population of the Netherlands suffers at some stage in their life from low back pain (Haanen, 1984) ; clinical examination of the lumbar spine is a matter of daily routine. X-Rays of the lumbar spine are taken in order to detect morphological changes that may be responsible for the patient's complaints. Sometimes, no abnormalities are found, and sometimes aberrations are found that may also be present in patients without low back pain, e.g. spondylosis, spondylarthrosis, scoliosis, disc space narrowing, spondylolisthesis etc. (Frymoyer, 1984; Witt, 1984). Another reason for taking X-Rays is that the doctor aims at gathering additional information about the function of the spine. For this purpose, XRays are made in different postures