QUANTITATIVE MORPHOLOGY OF THE LATERAL LIGAMENTS OF THE SPINE - ASSESSMENT OF THEIR IMPORTANCE IN MAINTAINING LATERAL STABILITY

Study Design. This study used human cadaveric material to examine the three-dimensional morphology and biomechanics of the superior and late ral costotransverse ligaments and the intertransverse ligament of the spine. Objectives. To provide descriptive and quantitative data on the morphology of the lateral ligaments of the spine and to assess their importance in maintaining lateral stability, especially regarding the pathogenesis of idiopathic scoliosis. Summary of Background Data. Liga ments have been reported as being able to stabilize the spine by mecha nical constraint and by neurologic feed-back. Midline spinal ligaments have been well studied but do not appear to be effective in maintaini ng lateral stability because of their sites of attachment. Lateral lig aments of the spine have not been adequately documented in the literat ure. Methods. The morphology, sites of attachment, and dimensions of t he superior costotransverse ligament, lateral costotransverse ligament , and intertransverse ligament from thoracic level 7 to thoracic level 10 were determined on 32 human cadavers. Results. The intertransverse ligament was found not to be a true ligament. The lateral costotransv erse ligament was a true ligament but did not have the characteristics appropriate for involvement in lateral stability. The superior costot ransverse ligament also was a true ligament and had all of the charact eristics appropriate for involvement in the active lateral balancing o f the spine. Conclusions. In contrast to the midline ligaments of the spine, the superior costotransverse ligament perhaps is the most impor tant ligament for active lateral balancing of the spine and warrants f urther study, particularly regarding the development of idiopathic sco liosis.