Classification

Rotatory subluxation is classifed into four types depending upon the degree of separation of the dens from the anterior arch of atlas:

Type I : Atlanto-dens distance <3 mm; transverse ligament intact

Type II: Atlanto-dens distance 3–5 mm; transverse ligament ruptured

Type III: Atlanto-dens distance >5 mm; alar ligaments ruptured

Type IV: Posterior subluxations of C1 on C2 (usually signifies an odontoid fracture or hypoplasia)

Explanation

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Figures

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Reference(s)

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