Structure on the capsular ligaments of the facet joints.

Microscopic studies showed that the capsular ligaments were mostly composed of collagenous tissue. The collagen fiber bundles were found to be crimped at right angles to their long axis. The collagen fibrils were connected transversely by proteoglycan filaments which were regularly associated with their periodicity. Among the collagen fiber bundles were varying quantities of elastic fibers and numerous fibroblasts. The highest concentration of elastic fibers was found in the posterior and inferior aspects of the capsular ligaments. These findings are discussed in relation to the mechanical behavior of the capsular ligaments.