The median atlanto-axial joint is the articulation between the anterior surface of the odontoid process and the posterior surface of the arch of the atlas. The axis of rotation of the joint is vertical and corresponds to the long axis of the odontoid process. The articulation between the odontoid process and the anterior arch of the atlas is a pivot joint with incomplete articular surfaces, since the odontoid process is frequently covered with cartilage upon its anterior surface only, its posterior surface articulating with the transverse ligament of the atlas by a separate joint. Both joints have separate capsules; the posterior one is also regarded as a synovial bursa. The capsule of the median atlanto-axial joint is roomy and relaxed. The articulation is provided with a series of accessory ligaments, which create an extremely firm connection between the head and the first two vertebrae.

Articulatio atlantoaxialis mediana

Articulation atlantoaxoïdienne médiane