atlantoaxial joint

The median atlantoaxial joint is sometimes considered a double joint:

The lateral atlantoaxial joint involves the lateral mass of atlas and axis.

The atlantoaxial joint in common terminology is actually a composition of three: two lateral and one median atlantoaxial joints.

The use of HVLA is contraindicated in patients with Down syndrome due to instability of the atlantoaxial joint which may stem from ligamentous laxity, and in pathologic bone conditions such as fracture, history of a pathologic fracture, osteomyelitis, osteoporosis, and severe cases of rheumatoid arthritis.