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 lateral 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

Ligaments have been reported as being able to stabilize the spine by mechanical constraint and by neurologic feed-back. Midline spinal ligaments have been well studied but do not appear to be effective in maintaining lateral stability because of their sites of attachment. Lateral ligaments of the spine have not been adequately documented in the literature.

METHODS

The morphology, sites of attachment, and dimensions of the 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 costotransverse ligament was a true ligament but did not have the characteristics appropriate for involvement in lateral stability. The superior costotransverse ligament also was a true ligament and had all of the characteristics appropriate for involvement in the active lateral balancing of the spine.

CONCLUSIONS

In contrast to the midline ligaments of the spine, the superior costotransverse ligament perhaps is the most important ligament for active lateral balancing of the spine and warrants further study, particularly regarding the development of idiopathic scoliosis.