The anatomy, spatial relationships, and role of uncovertebral articulations as the source of posterolateral cervical cartilage sequestrations Laboratory investigation

Object. The aim of this study was to investigate the spatial relationships of the uncovertebral articulations (UAs) with the dural origins of the C-5, C-6, and C-7 nerve roots. Methods. The C3-7 segment of the cervical spine was removed from 18 embalmed cadavers. Spatial relationships between the C-5, CA and C-7 nerve roots and the UAs were examined using combinations of standard surgical approaches together with cross-sections at the level of the dural origins of the nerve roots and exposures of the floor of the spinal canal. Results. The cartilaginous interspace that underlies the dural origin of a nerve root is the interspace of a UA. It is interposed between the central core cartilage of the disc and the dural origin of a nerve root. Cervical nerve roots do not come in contact with the interspace of an intervertebral disc at any site from their dural origin to their exit from the spinal canal. A cartilage fragment that originates from the central core cartilage of the disc may compress the intradural segment of the nerve root by migrating to that site within the epidural space, but it is blocked from reaching the dural origin of a nerve root by the interspace of a UA that is filled with fibrocartilage. Conclusions. Anatomical considerations indicate that the source of posterolateral cervical cartilage sequestrations is the cartilaginous interspace of a UA rather than that of an intervertebral disc. (DOI: 10.3171/2009.10.SPINE09367)