Cervical pedicles: Correcting a common misconception

Abstract

To bring to the attention of Australian radiologists in training, directors of training and radiologists in general, a commonly held erroneous misconception, specifically that of the plain radiographic appearance of the cervical spine pedicle and the transverse process in oblique projections. A human C5 vertebra was appropriately marked and radiographed in the oblique projection to demonstrate key anatomical structures and their relations. The rounded cortical contour overlying the vertebral body is commonly misinterpreted as a cervical transverse process but is the plain radiographic outline of the end-on ipsilateral pedicle. Because of the right-angle relationship of the transverse process long axis and the end-on pedicle long axis, the ipsilateral transverse process appears as a faint elongated corticated structure projecting beyond the vertebral body contour. It may also be obscured because of small size, relative osteopaenia and overlying soft tissue bulk. The end-on pedicle has been unequivocally demonstrated, as has the ipsilateral transverse process. The two lie at right angles to each other. The common misconception (amplified by an error in an earlier edition of a popular atlas) should be debunked by radiologists and should not be promulgated to Australian radiology trainees.