The oblique anteroposterior (OAP) diameter of the articular pillar
is representative of the screw length by Magerl method with average OAP diameter reported from 10.
Cervical spondylolysis is, however, much more rare than its lumbar counterpart and is described as a well-corticated cleft between the superior and inferior articular facets of the articular pillar of the cervical spine.
Plain-film radiography and CT are the principal diagnostic modalities that help in differentiating cervical spondylolysis from articular pillar fracture or dislocation.
In patients suffering a fractured articular pillar or facet, a unique phenomenon known as the "double outline sign" may be present on radiographic images.
Fractures of the articular pillar or facet are usually stable and can be confirmed with CT scan.
Upon completing a cervical spine series, the radiologic technologist reviews the AP projection to ensure that the articular pillars and facets are visualized.
It has also been suggested that for increased comfort during a unilateral posteroanterior (P/A) pressure the paravertebral musculature should be pushed laterally so that the bulk of this muscle is not squashed against the underlying articular pillar
(Edmondston & Elvey 1997).
In the cervical and lumbar regions this gutter is shallow, formed mainly by the laminae and articular pillars
, whereas in the thoracic region the gutter is deeper and broader, being formed by the laminae, articular pillars
and transverse processes.