Accessory articulation of cervical vertebral transverse process: a rare case

There are several anatomical variants of the cervical vertebrae described in literature ranging from benign findings to those with varying clinical implications, including association with congenital diseases. We describe a case of an extremely rare anatomical variant of the cervical spine consisting of an accessory articulation of the cervical vertebrae C4 and C5 right transverse processes. The case is of a 35-year-old female who presented to primary care with 6-week history of intermittent, dull neck pain. An X-ray of the cervical spine was obtained which did not demonstrate radiological evidence of an acute fracture, dislocation, nor vertebral collapse. However, the X-ray revealed subtle multilevel anterior marginal osteophytic lipping. As a minor fragmented fracture or osteophytic growth could not be excluded; the patient proceeded to have a CT of the cervical spine. This revealed an accessory articulation of both the C4 and C5 right transverse processes, an extremely rare anatomical variant. Our comparison of both X-ray and CT imaging modality results highlighted the importance of utilising CT in identification in the accessory articulation anomaly, which aids in directing patient to appropriate care. Although similar cases may have been seen in clinical practice, to our knowledge, there are no previously documented C4-5 accessory articulations in the literature.