Atlas-Dens Interval (Adi) in Children

‘35 I N JULY, 1964, an 8 ‘ear old girl was admitted to tile State University of Iowa Hospitals with multiple injuries sustained in an automobile accident. Although she died soon after admission, numerous roentgenograms were obtained before death. A lateral roentgenogram of the cervical spine revealed a distance of3. mm. between the anterior portion of the atlas and the dens (odontoid process) of the axis (Fig. ). This raised the question of atlanto-axial dislocation. Autopsy was refused by the parents. A comparison of the atlas-dens interval (ADI) on roentgenograms taken before and after death revealed no change in the measurement. Stimulated by this finding, we measured the interval between the atlas and the dens in a normal 8 year old child and found the same distance, 3.5 mm. A hurried review of the literature revealed no adequate study of the ADI in children.’4 The present study was then initiated.