Radiography and X-Ray Tomography

Plain X-ray films of the craniocervical region including the open mouth projection are essential. There are many anatomical and projectional variations of the cervical spine in this region. It is essential to be familiar with these in order to distinguish normal from pathological (Wackenheim 1974). Nicolet et al. (1984) for example described an apparent hyperostosis of the C2 body which was found to be a projectional variant and not an osteoid osteoma. 

The distance from the posterior aspect of the anterior arch of the atlas to the anterior aspect of the odontoid process is less than 3 mm in adults. A larger distance bespeaks atlantoaxial dislocation. The antero-posterior diameter of the spinal canal in the atlanto-axial region is 20-26 mm in men and 19-25 mm in women. According to Apuzzo et al. (1978), patients develop clinical symptoms when the anteroposterior diameter is less than 14 mm at C1-C2 level. 

Traumatic lesions, fractures, osteolytic erosion of tumorous and inflammatory origin are readily detectable on tomograms. In inflammatory processes there may be an increased width of the retropharyngeal soft-tissue space on lateral view. 

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