Atlantoaxial subluxation with cord compression

84-year-old patient with rheumatoid arthritis who had undergone C2-5 laminectomies previously. (A) Sagittal short-tau inversion recovery (STIR) and T2-weighted (B, C) magnetic resonance images of craniocervical junction in neutral position demonstrate upper cervical cord compression (small asterisks) from atlantoaxial subluxation and pannus (large asterisks). Abnormal anterior atlantodental interval (small double-headed arrows) measures 7 mm and posterior dental interval (large double-headed arrow) measures 12 mm. In addition to cord compression, STIR image (A) also shows mild hyperintensity within cervical cord caudal to site of most severe cord compression.