Abstract
Serial measurements of intervertebral angles from L2-5 were carried out during sidebending in two asymptomatic subjects, using digital videofluoroscopy. One subject exhibited free motion at all three functional spinal units (FSUs), whilst the other had a fixation at L4/5. Both subjects demonstrated irregular motion at the mobile FSUs. However, these irregularities were simultaneously compensated for as the motion progressed, especially in the fixation-free subject. The results lend anecdotal support for the notion that freedom from joint fixation promotes integrated spinal motion. However, further studies and larger numbers will be necessary to confirm or refute this.