title: Os odontoideum: an acquired lesion.
mesh_terms: D001174:Arthrodesis; D001368:Axis, Cervical Vertebra / Q000000981:diagnostic imaging*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010146:Pain / Q000209:etiology; D013122:Spinal Diseases / Q000000981:diagnostic imaging* / Q000601:surgery; D014056:Tomography, X-Ray; D014103:Torticollis / Q000209:etiology; D014143:Traction