[2 cases of os odontoideum with atlanto-axial dislocation].
D001368:Axis, Cervical Vertebra / Q000002:abnormalities* / Q000293:injuries*; D001270:Cervical Atlas / Q000293:injuries*; D006801:Humans; D004204:Joint Dislocations / Q000150:complications*; D008297:Male; D008875:Middle Aged