Axis

Axis is the second cervical vertebra that, together with the first one — atlas — provides about 50% of the cervical spine's total axial rotation*.

  • * Panjabi MM, Dvorak J et al. Three dimensional movements of the upper cervical spine. Spine, 1988;13(7):370-378.
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    Icon of crossfade image Anterior view of axis with the anatomical terminology markup
    Anterior view of axis
    Axis. Anterior aspect.
    The most prominent feature of that vertebra is the teeth-shaped process — dens axis.
    The list of terms: Corpus vertebrae – Body of vertebra
    Dens axis – Dens of axis
    Apex Dentis – Apex of dens
    Facies articularis anterior – Anteriror articular surface of dens
    Processus articularis superior – Superior articular process
    Processus articularis inferior – Inferior articular process
    Processus transversus – Transverse process
    Icon of crossfade image Top view of axis with the anatomical terminology markup
    Top view of axis
    Axis. Superior aspect.
    Another feature of this vertebra is the convex shape of the articular surface of processus articularis superior, which is not congruent to the adjacent articular surface of the axis, allowing some lateral bending and flexion-extension movements between atlas and axis*.
    The list of terms: Corpus vertebrae – Body of vertebra
    Dens axis – Dens of axis
    Arcus vertebrae – Vertebral arch
    Lamina arcus vertebrae – Lamina of vertebral arch
    Foramen vertebrale – Vertebral foramen
    Apex Dentis – Apex of dens
    Facies articularis anterior – Anterior articular surface of dens
    Processus articularis superior – Superior articular process
    Processus articularis inferior – Inferior articular process
    Processus spinosus – Spinous process
    Processus transversus – Trnasverse process
  • * Zhao X, Wu Z et al. Three-dimensional analysis of cervical spine segmental motion in rotation. Arch Med Sci, 2013;9(3):515–520.
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    Icon of crossfade image Side view of axis with the anatomical terminology markup
    Side view of axis
    Axis. Lateral aspect. Compared with other cervical vertebrae, the axis has two extra articulatory surfaces on both sides of the dens – facies articularis anterior & posterior.
    The list of terms: Corpus vertebrae – Body of vertebra
    Dens axis – Dens of axis
    Apex Dentis – Apex of dens
    Lamina arcus vertebrae – Lamina of vertebral arch
    Processus articularis superior – Superior articular process
    Processus articularis inferior – Inferior articular process
    Processus spinosus – Spinous process
    Processus transversus – Transverse process
    Icon of crossfade image Iso view of axis with the anatomical terminology markup
    Iso view of axis
    Axis. The isometric aspect.
    The list of terms: Corpus vertebrae – Body of vertebra
    Dens axis – Dens of axis
    Apex Dentis – Apex of dens
    Facies articularis anterior – Anterior articular surface of dens
    Facies articularis posterior – Posterior articular surface of dens
    Arcus vertebrae – Vertebral arch
    Processus articularis superior – Superior articular process
    Processus transversus – Transverse process
    Foramen transversarium
    Axis. 360° rotation.
    First published: Jan/2019
    Last update: 24/Nov/2020