Joints of Cervical Spine C1 and C2

Atlas

No body, has two lateral masses united by two arches

Features of atlas

one = anterior arch with anterior tubercle, two = posterior arch with posterior tubercle, three = transverse processes with transverse foramina, four = superior articular facets, five = inferior articular facets, six = facet for dens

Axis function

Provides axis of head

Features of axis

One = body, two = spinous process, three = transverse process with transverse foramina, four = superior articular facets, five = inferior articular facets, six = dens

Atlanto-occipital joint classification

Synovial biaxial ellipsoid

Atlanto-occipital joint articular surfaces

Superior articular facets of c1 and occipital condyles of skull

Atlanto-occipital joint articular capsules

thin and loose

Atlanto-occipital joint movements (head)

Flexion and extension, lateral flexion and rotation coupled contralaterally

Anterior atlanto-occipital membrane 

From anterior arch of c1 to anterior margin of foramen magnum, limit all movements of atlanto-axial joints

Posterior atlanto-occipital membrane

From posterior arch of c1 to posterior margin of foramen magnum, limit all movements of atlanto-axial joints

Median atlanto-axial joint classification

Synovial uniaxial pivot

Median atlanto-axial joint articular surfaces

Facet for dens on anterior arch of c1, dens of c1 and transverse ligament of atlas

Two lateral atlanto-axial joints classification

Synovial multiaxial plane

Two lateral atlanto-axial joints articular surfaces

Inferior articular facets of c1 and superior articular facets of c2

Movements of atlanto-axial joints (head)

Rotation, c1 and the head rotate as a unit on c2

Transverse ligament of atlas - atlanto-axial ligaments

Spans between two lateral masses of c1, wraps posteriorly around dens of c1 to hold it in place against anterior arch of c1, limits anterior glide of c1 during flexion

Bands of transverse ligament of atlas

Superior band to anterior margin of foramen magnum, inferior band to posterior surface of body of c2

Cruciform ligament - atlanto-axial ligaments

Transverse ligament of atlas and longitudinal bands combined, limits flexion

Apical ligament of dens - atlanto-axial ligaments

From tip of dens to anterior margin of foramen magnum, anterior to superior longitudinal band of cruciform ligament

Alar ligaments - atlanto-axial ligaments

From tip of dens to medial sides of occipital condyles, limits flexion lateral flexion and contralateral rotation of head

Tectorial membrane - atlanto-axial ligaments

Superior continuation of posterior longitudinal ligament, from posterior surface of body of c2 to anterior margin of foramen magnum, posterior to cruciform and alar ligaments, limits head flexion

Anterior atlanto-axial membrane

From anterior arch of c1 to anterior surface of body of c2

Posterior atlanto-axial membrane

From posterior arch of c1 to vertebral arch of c2

Ligamentum nuchae

Not a true neck ligament, fibroelastic septum in midline of posterior neck, from spinous process of c7 to occipital bone, superior continuation of supraspinous ligament