The atlas is the first cervical vertebra. As the part of the Spine closest to the skull, it supports the entire head and, together with the Axis, forms a closely integrated functional unit.
Anatomy
The atlas differs fundamentally from the other vertebrae in that it lacks a body. The atlas is described as having an anterior arch and a larger posterior arch. Each arch has a small tubercle in the median plane, the anterior tubercle and the posterior tubercle. Lateral to the foramen vertebrale are the lateral masses, each of which bears a superior articular facet and an inferior articular facet. On the inner aspect of the anterior arch is the fovea dentis with an articular surface. From the Foramen transversariumArteria vertebralisSulcus arteriae vertebralis.
Anatomical variants
Instead of the sulcus arteriae vertebralis, a Vertebral artery canal (ponticulus posticus) may also be present.[^1]
Figure
Clinical relevance
The anterior tubercle of the atlas serves as an anatomical landmark for identifying the midline during a transoral approach[^2].