A MORPHOLOGICAL-STUDY OF THE FIBROUS CAPSULE OF THE HUMAN LUMBAR FACET JOINT

Study Design. Macroscopic and microscopic investigations of the human lumbar facet joint capsule were undertaken. Objective. To describe the morphologic characteristics of the fibrous capsule of the lumbar face t joints. Summary of Background Data. Previous biomechanical and neuro physiologic studies by the authors have shown that the lumbar facet jo int capsule may be a source of low back pain. Methods. Macroscopic inv estigation was performed on the facet joint capsules dissected from fi ve fresh adult cadavers. For microscopic studies, facet joint capsules obtained from cadaver dissection and spinal surgeries were stained by the hematoxylin and eosin method and the Elastica-Van Gieson method. Results. The outer layer of the fibrous capsule is a dense regular con nective tissue that is composed of parallel bundles of collagenous fib ers. The inner layer of the fibrous capsule consists of bundles of ela stic fibers, similar to the ligamentum flavum. In the superior and mid dle part of the joint, the fibers run in the medial to lateral directi on, crossing over the joint gap. In the inferior part of the joint, th e fibers are relatively long and run in a superior-medial to inferior- lateral direction, covering the inferior articular recess. They are th icker than the layer in the superior and middle parts of the joint. Co nclusions. Anatomical and histologic features of the lumbar facet join t capsule are different between its outer layer and inner layer. This complex of morphologic factors can affect the biomechanics and neuroph ysiology of the lumbar facet joint.