Atlanto-occipital and Atlanto-axial joint

Atlanto-occipital joint

-(articulation between the atlas and the occipital bone) consists of a pair of condyloid joints.

ligaments connecting the bones are:
1.Two Articular capsules
- synovial joint of condyloid type, loose capsules

2.Posterior atlantoöccipital membrane
broad but relatively weak
extend from anterior arch of atlas to posterior margin of foramen magnum

3.Anterior atlantoöccipital membrane
- broad, densely woven fibre ( strong)
- centrally they are continuous with anterior longitudinal ligament
- extend from anterior arch of atlas to anterior margin of foramen magnum

The movements permitted in this joint are:
1.flexion and extension, which give rise to the ordinary forward and backward nodding of the head
2.slight lateral motion to one or other (tilting of head)

Atlanto-axial articulation

-articulation of the atlas with the axis

three articulation facet:

2 lateral atlanto-axial joint (right and left)
- betweeen inferior facet of lateral mass of atlas and superior facet of axis.
- gliding type synovial joint

1 median atlanto-axial joint
- between den of axis and anterior arch of atlas
- pivot joint

movement permitted at this joint:
1.rotation of head
- cranium and atlas rotate on axis as a unit
- the dens of C2 is the pivot that is held in the socket formed by the tranverse ligament of the atlas

Ligament connecting the bone:
1.Superior and inferior longitudinal ligament (cruciate ligament)
- pass from transverse ligament to occipital bone superiorly and to body of C2 inferiorly
2.Alar ligament
-extend from side of transverse ligament to lateral margin of foramen magnum
3.Tectorial membrane
- strong superior continuation of posterior longitudinal ligament across the median atlanto-axial joint through foramen magnum to the centre floor of cranial cavity.
- run from C2 to internal surface of occipital bone covering alar and transverse ligament
4.Transverse ligament
- extend between the tubercles of the medial aspects of the lateral mass of C1 verterbrae


Contributed by Lawrence Oh