Degeneration of the atlanto-axial joints: a histological study of 9 cases.

Degeneration of the lateral atlanto-axial joints (AAJ) has been described as a potential cause of severe neck pain. However, hardly any data are available on its incidence, especially in comparison to the lower cervical spine. In this histological study, we examined the AAJs in 9 specimens from elderly patients, graded the findings and compared them to those in the facet joints of the lower cervical spine. Most histological changes in the AAJs were mild, but the changes in the lower cervical spine were severer. Previous mechanical studies have described the AAJ as a very mobile joint with large neutral zones, which may explain the mild degree of osteoarthrosis found in these specimens.