• There is marked basilar invagination with the odontoid process projecting into the floor of the foramen magnum. The tip of the odontoid process lies roughly 8mm above the Mc Rae line. In addition, there is coronal malalignment of the peg which lies just left of midline.
• There is anterior subluxation of C1 over C2 with increased distance between the anterior C1 arch and peg. Moreover, there is partial assimilation/fusion of the lateral masses of C1 with the left and right occipital condyles. There is marked degenerative change associated with the tip of the odontoid process with remodelling of the clivus tip. No significant pannus formation or soft tissue swelling is seen to suggest an underlying inflammatory component.
• Otherwise there is loss of the normal cervical lordosis with severe moderate degenerative changes throughout the cervical spine most pronounced at the C6/C7 disc level with anterior claw osteophytes. No destructive bony lesion is seen. There is no underlying congenital vertebral body anomaly to account for the mentioned findings.
• Conclusion: Prominent basilar invagination as outlined above with coronal malalignment of the peg, anterior subluxation of C1 and partial fusion of C1 with the occipital condyles in keeping with assimilaition. I note the MRI shows prominent cord signal change. Does the patient have a history of rheumatoid arthritis to account for the basilar invagination?