Preschooler with Trisomy 21 Pediatric Imaging Neurological September 27, 2022August 18, 2022 Lateral radiographs of the cervical spine show a mildly enlarged atlanto dens interval in neutral position (left), that increases significantly on flexion (center) and reduces on extension (right). The diagnosis was atlanto axial instability in a patient with Trisomy 21. Related Published September 27, 2022August 18, 2022