PMC5288981_01
(a) Lateral radiograph. An oblique fracture of the axis is observed. The fracture line extends obliquely from posterior elements to the vertebral body (white arrows). The fracture line divides obliquely the axis vertebra in two fragments. Note the C2-C3 intervertebral space fusion (black arrow). (b) Axial CT. There is an absence of midline fusion of anterior C1 arch (white arrow). The presence of sclerosis of both borders indicates that this is not a fracture. (c) Axial CT. This image shows the fracture in the body of C2 (curve arrow). The fracture line in the posterior elements runs through supero-anterior border of the pars and foramina transversarium (straight arrow). (d) 3D CT reconstruction. The posterior arch of C1 is incomplete (short arrow). Also note the absence of right C2-C3 articular space (long arrow) and fusion of laminae. The fracture line in the body of the axis is also observed (curved arrows). (e) Lateral radiograph showing adequate alignment after treatment with halo-vest. Note the bridging callus in the anterior border of the C2 body
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F1
Furthermore, the anterior C1-arch was bifid and there was a partial agenesis of the posterior C1 arch [Figure 1a-d]. Following immobilization in a halo vest for 3 months, the fracture fused, maintaining adequate alignment [Figure 1e].