Atlantoaxial Instability
Additional Information
Atlantoaxial instability (AAI) refers to an abnormal, excessive movement between the first (atlas or C1) and second (axis or C2) cervical vertebrae, which can lead to cervical vertebrae instability. This condition is typically caused by congenital abnormalities (such as Down syndrome), inflammatory diseases (like rheumatoid arthritis), or trauma. The resultant laxity poses a risk of spinal cord compression.