Entwicklungsstörungen am atlanto-okzipitalen Übergang

Diagnostic Criteria of Basilar Impression

“…In addition, a perpendicular drawn from the apex to the reference line should intersect it in its ventral quarter. Otherwise neurologic disturbances can be expected (3).…”

Accessory joints between basiocciput and atlas/axis in the median plane

“…When a median osseous process is found to exist on the anterior margin of the foramen magnum it is taken to be a TOC, which can be of various shapes and sizes and located in various positions (Le Double, 1903;Oetteking, 1923;Bystrow, 1931;Decker et al, 1956;Kamieth, 1959;Habel, 1965;Prasada Rao, 2002). Occasionally, such a tubercle in a median position exhibits an articular facet (Hyrtl, 1889;Kalenscher, 1893;Neiss, 1964;Hauser and De Stefano, 1989;Lang, 1995).…”

“…A TOC has occasionally been recognised radiologically, appearing as a tiny and small or bulky and large bony element, either attached to the anterior margin of the basiocciput or unfixed (free) between the occipital bone and the anterior arch of the atlas or the tip of the dens axis. In traditional X-rays the presentation of a TOC deep within the vertebral region is blurred and often unclear (Decker et al, 1956;Schmidt, 1959;Lombardi, 1961;Fischer, 1963;Wackenheim, 1974;Putz, 1975;Holthusen, 1989). A TOC may or may not have an osseous counterpart to the atlas or even the tip of the dens axis.…”