Like typical joints found in the human body, the joints of the vertebral column are formed by the union of two or more bones. The types of joints formed along the vertebral column include;
-Joints of the vertebral arches known as zygapophysial joints,
-Joints of the vertebral bodies,
-and Sacoiliac joints.
Craniovertebral joints are types of joints formed by the connection between the cranium or skull and the vertebral column. There are two types of craniovertebral joints; the atlanto-occipital joints and the atlantoaxial joints. Both these joints are synovial joints and they have a wider range of motion than other joints of the vertebral column.
The atlanto-occipital joint, as the name suggests, is formed between the occipital condyles and the superior articular surface of the atlas. Where as the atlantoaxial joint which is formed between the atlas and the axis, is actually comprised of two lateral atlantoaxial joints and one median atlantoaxial joint.
The atlanto-occipital joint permits movements such as flexion and extension, for example when nodding the head, as well as lateral flexion and rotation. While the atlantoaxial joints permit rotational movement, such as when we shake our heads in disapproval of something.
Ligaments associated with these joints include the interspinal ligament, the apical ligament of dens, the posterior atlanto-occipital ligament, the anterior longitudinal ligament, the posterior longitudinal ligament, the nuchal ligament, the transverse ligament of the atlas, ligamentum flavum and cruciform ligament of the atlas.
These ligaments function to strengthen and stabilize the joints.
Other structures include the anterior and posterior atlanto-occipital membranes which connect the cranium and the atlas, the tectorial membrane which is a continuation of the posterior longitudinal ligament, and the anterior atlantoaxial membrane.
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