title: Atlantoaxial distance in patients with Down syndrome: standardization of measurement.
abstract: Atlantoaxial subluxation is common in persons with Down syndrome. For radiologic screening to be valid, accurate measurement of the atlantoaxial distance (AAD) must be obtained from radiographs of the cervical spine. A radiopaque millimeter scale has been designed to simplify accurate measurement of the AAD from these radiographs.
mesh_terms: D001268:Atlanto-Axial Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D002675:Child, Preschool; D004314:Down Syndrome / Q000150:complications*; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000000981:diagnostic imaging* / Q000209:etiology; D011859:Radiography; D012016:Reference Values