Spine Normal Variants

Lustrin ES, Karakas SP, Ortiz AO et al (2003) Pediatric cervical spine normal anatomy, variants and trauma. Radiographics 23 539-560... 

In this chapter, the anatomy, normal variants and injuries to the paediatric spine are discussed with emphasis on the role of imaging and the concept of stability. 

A number of normal variants are seen in the paediatric spine. These are usually due to variations in ossification and also due to hyper mobility of the spine. Consequently, these are more common in the upper cervical spine due to the hyper-mobility and complexity of ossification in this region. 

It is vitally important to be aware of the anatomical variants and normal developmental findings that may be present in the paediatric spine, as many of these can be confused with significant injury in the context of trauma. Imaging of the paediatric cervical spine presents a particular challenge since not... 

Anterior wedging of the upper cervical bodies particularly C3 (Fig. 7.62) is a normal developmental variant and should not be confused with a compression injury. It may be the result of relative hypermobility of the spine during childhood and resolves with increasing maturity (Swischuk et al. 1993). Secondary ossification centres ( ring epiphyses or apophyses) appear at the superior and inferior aspects of all vertebral bodies and do not fuse with the vertebral body until early adulthood (Figs. 7.63, 7.64). These should not be mistaken for fractures, although they can be avulsed as a result of trauma (JOHNSSON et al. 1991). 

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. 

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