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Sagittal high power photograph of the
L4–L5 facet joint and foramen in a spine that had been positioned in
extension in the intact cadaver and frozen in situ to maintain the
undistorted soft tissue–bone relationships. The extension was done
without any axial loading. The extension position induces a
posterior sagittal rotation of L4 on L5. In addition, the slight
obliquity of the facet joint induces a slight posterior translation
of L4 on L5. The extension also causes the tip of the inferior
articular process to come in contact with the pars interarticularis
of L5 which also is in contact from inferiorly with the superior
articular process (SAP) of S1. The joint capsule is elongated and
severely compressed against the pars interarticularis. The degree of
angulation is also apparent from the wedge–shaped opening of the
superior joint space into which a richly vascularized meniscoid
synovial tag of loose areolar is projecting. The ligamentum flavum
joint capsule attaches broadly to the anterior surface of the SAP.
It is pushed into the subpedicular notch and compresses and flattens
the dorsal root ganglion posteriorly. Anterior to the ganglion the
separate ventral roots are discernible. |
©2000 Wolfgang Rauschning, M.D., Ph.D.
Professor of Clinical Anatomy
Academic
University Hospital
Department of Orthopaedic Surgery
Uppsala, Sweden
Reproduction without permission is prohibited
http://www.akademiska.se/
