Description
The atlantoaxial joint is a pivot synovial joint between the atlas and axis vertebrae. The vertebrae communicate with each other at three separate synovial joints; two lateral plane synovial joints and one median pivot joint.
The lateral atlantoaxial joints are comprised of the lateral masses of the atlas and the sloping superior articular facets of the axis, which are bound and supported by an articular capsule. These lateral joints are typically classified as plane synovial joints.
The median atlantoaxial joint is a pivot joint formed by the dens (odontoid process) of the axis articulating with the anterior arch of the atlas.
The atlantoaxial joints are supported by a variety of ligaments which contribute to the joint’s freedom of movement. These ligaments are the surrounding joint capsules, anterior longitudinal ligament, posterior ligamentum flavum, the transverse ligaments of the atlas, and the cruciate ligaments. The axis is connected to the occipital bone via the tectorial membrane, the alar ligaments, the median apical ligament, and the longitudinal segments of the cruciate ligaments.