Cervical spine bones and ligaments: joints (Latin)

The atlas articulates with the os occipitale at the art. atlantooccipitalis, which presents the primary connection of the head with the trunk. This is a junctura synovialis formed by the condyli occipitales and facies articularis superior atlantis. The joint is secured by the membranae atlantooccipitales anterior et posterior and allows for flexion and extension of the head, as well as a limited degree of lateral flexion.The atlas and axis articulate via a complex art. atlantoaxialis. This joint consists of three synovial components: a single art. atlantoaxialis mediana and paired artt. atlantoaxiales laterales. The main movement of this complex joint is the axial rotation of the head, but it also allows limited flexion, extension and lateral flexion.The art. atlantoaxialis mediana (a.k.a. atlantodental joint) is formed by the dens axis, arcus anterior atlantis and lig. transversum atlantis. It is composed of two elements: an articulation between the facies articularis anterior dentis axis and fovea dentis located on the internal surface of the arcus anterior atlantis, as well as a second articulation between the facies articularis posterior dentis axis and the anterior surface of the lig. transversum atlantis. The joint is primarily reinforced by the lig. cruciforme which consists of the lig. transversum atlantis, fasciculi longitudinales superior et inferior ligamenti cruciformis. Additional support is provided by the membrana tectoria, ligg. alaria, lig. apicis dentis, membranae atlantoaxiales anterior et posterior.The left and right artt. atlantoaxiales laterales are formed by the facies articularis inferior of the massae laterales atlantis with the facies articularis superior of the axis. They are reinforced by several ligaments e.g. the ligg. atlantoaxiales accessoria, membranae atlantoaxiales anterior et posterior, membrana tectoria etc.