Intervertebral joint
There are three intervertebral joints between each adjacent vertebra from the axis to the sacrum – one between the vertebral bodies and a pair between the facets of adjoining vertebral arches (zygapophysial joints, also called facet joints).
Gross anatomy
Movement
- flexion: the anterior intervertebral disc compresses; the inferior articular processes will move upward as the gap between the laminae widen; the anterior longitudinal ligament relaxes while the posterior longitudinal, ligamentum flavum, inter- and supraspinous ligaments stretch
- extension: the opposite of the above occur, however extension is limited by the anterior longitudinal ligament and the physical shape of spinous processes
- lateral flexion: the lateral intervertebral disc compresses and is limited by resistance from all adjacent ligaments
- rotation: via the twisting of the intervertebral discs
- in the cervical spine the elevated angle of the articular processes allows for increased flexion and extension
Articulations
- intervertebral cartilaginous joint: the inferior and superior surfaces of the vertebral bodies are covered by a layer of hyaline cartilage. The fibrocartilaginous intervertebral disc then adheres to these layers of cartilage between the adjacent vertebral bodies. The discs are wedge shaped, being slightly thicker in the anterior aspect in the cervical and lumbar spines, which produce the convexities of those regions, while fairly uniform in the thoracic spine.
- intervertebral synovial facet joint: each vertebra has two superior and two inferior articular facets found on the vertebral arch, between the pedicle and lamina, which are covered in articular cartilage. These articulate with the corresponding facets of the vertebrae above and below. This articulation is surrounded by a synovial capsule.
Attachments
- anterior and posterior longitudinal ligaments: support the intervertebral cartilaginous joints and run down the anterior and posterior aspects respectively of the vertebral bodies and discs from the skull to sacrum
- the zygapophysial joint is supported by the posterior ligamentous complex (facet joint capsule, ligamentum flavum, interspinous ligament, supraspinous ligament)