Physical exam On palpation, the examiner may find crepitus at the neck joint and unstable movement including a positive "clunk test" (palpable subluxation). Lhermitte's sign may be elicited with head flexion. Imaging As many as 50% of people with radiographic instability are actually asymptomatic. Initial radiography should include flexion and extension lateral X-rays in addition to static anterior/posterior and lateral views. These views are often repeated every 2–3 years, especially in patients with new symptoms or possibly requiring future intubation. Progression of<unk>  is measured via anterior atlantodental interval (AADI), and posterior atlantodental interval (PADI). Other techniques include the Ranawat Index, MacGregor Line, the Clark stations, and the Redlund-Johnell measurement.
Rheumatoid disease of the spine
Spondylolysis
Spondylosis deformans
Neuropathic arthropathy
Axial spondyloarthritis
Ankylosing spondylitis
Spinal disc herniation
Vertebral osteomyelitis