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Normal atlantodental distance (C1-C2)

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History

Distance between the anterior surface of the dens and the posterior surface of the tubercle of C1 (predentate space, predental space, atlantodental distance):

Normal ≤ 3 mm in adults

Normal ≤ 5 mm in children

 

Atlantoaxial instability: increase in the predentate space of greater then 3 mm in adults and 5 mm in children

 

 

 

Anterior atlantoaxial dislocations may be associated with a fracture of the dens (~50% at autopsy. This injury is unstable. Associated fractures of the skull and/or facial bones are common.

Almost all atlantoaxial dislocations involve forward movement of C1 on C2; posterior dislocation is extremely rare.

 

Chronic atlantoaxial dislocations may be asymptomatic, and occure in different diseases (non traumatic): Down syndrome, Grisel syndrome, Rheumatoid arthritis, Osteogenesis imperfecta, Neurofibromatosis, Morquio syndrome, Psoriasis, Lupus.

See results

Author
Dr Antoine Micheau
Organization
CHU Arnaud de Villeneuve
Channel
Radiological classifications commonly used in medical imaging
Atlantoaxial Subluxation/Dislocation Normal-atlantodental-distance-C1-C2

Normal-atlantodental-distance-C1-C2