Corpus: Transverse ligament of the atlas

The ligamentum transversum atlantis is a short, very strong ligament that stretches out in the bony ring of the atlas and holds the dens axis in position.

The ligamentum transversum atlantis runs concave ventrally and is wider in the centre than at either end. It is attached on both sides to a small tubercle on the medial surface of the two atlas arches. In the area of the articulatio atlantoaxialis mediana, the ligament contains cartilage tissue.

At the level of the dens axis, it sends a small fibre strand (crus superius) cranially to the occipital bone and another fibre strand (crus inferius) caudally to the dorsal surface of the vertebral body of the axis. These fibre cords - also called fasciculi longitudinales - together with the ligamentum transversum atlantis are referred to in their entirety as the ligamentum cruciatum atlantis.

The transverse atlantal ligament divides the vertebral foramen of the atlas into two parts. The anterior part contains the dens axis, the posterior part contains the spinal cord and the spinal meninges.

Between the ligament and the dens axis is a small bursa, the bursa atlantodentalis.