Anterior displacement of C₂ in children: Physiologic or pathologic? A helpful differentiating line

Differentiating pseudo dislocation of the cervical spine from true fracture dislocation of C₂ on C₃ is often difficult in children. Normal anterior position of C₂ on C₃ secondary to normal mobility of this area may be so pronounced that it seems true dislocation is present. A helpful line is presented to aid in the solution of this problem and the anatomy of normal and abnormal (fracture dislocation) motion at the C₂-C₃ level will be discussed.