Cx Joints Flashcards
Which joints are present in the cervical spine?
OA joint (Atlanto-occipital) - between C1 and occiput
AA joint (Atlanto-axial joint) - between C1 and C2
Joints between C2-7:
- intervertebral joint (medial)
- facet / zygapophyseal joints (bilateral)
joints between C2-6:
- uncinate joints / joints of Luschka (medial)
At what levels are the uncinate joints present?
C3-6 (present in the cervical spine only)
Describe the OA joint
OA joint (axio-occipital) is between the C1 Axis and the occipital condyles of the skull.
It is a condyloid synovial joint, allowing for small sagittal motions of flexion and extension, with lateral flexion also available.
The articulation is between the concave superior articular facets of the C1 and the convex occipital condyles of the occipital bone of the skull.
The joint is supported by the anterior and posterior atlanto-occipital membranes (from the anterior and posterior arches to the margins of the foramen magnum)
Which are the 2 ligaments that support the OA joint?
The anterior and posterior atlanto-occipital membranes specifically support the OA joint (and other craniocervical ligaments provide additional support).
The anterior and posterior atlanto-occipital membranes have their origins on the anterior and posterior arches of C1 respectively, and insert onto the anterior and posterior margins of the foramen magnum respectively.
Which movements are available at the OA joint?
There are 3 movements available at the OA joint:
5 degrees of flexion
10 degrees of extension
10 degrees of lateral flexion (5 each way)
Describe the AA joint
The AA joint is the atlanto-axial joint, an articulation between C1 and C2.
There are 3 articulations that make up the AA joint:
the median pivot joint between the dens of C2 and the anterior arch of the C1, and 2 lateral zygopophyseal joints between the superior articular facets of C2 and the inferior articular facets of C1.
The primary movement available at the AA joint is rotation - there is a total 90 degrees of rotation (45 degrees each way) available, and this provides much of the range for rotational movement of the head.
There is also 5 degrees of flexion and 10 degrees of extension available.
The AA joint is supported by 3 additional ligaments:
* the cruciate ligament of the atlas
(transverse ligament = superior & inferior longitudinal bands)
* the alar ligaments
* the tectorial membrane
Which movements are available at the AA joint?
5 degrees of flexion
10 degrees of extension
90 degrees of rotation (45 degrees each way) - this provides 50% of the total rotation available at the cervical spine.
Which ligaments support the AA joint?
There are 3 additional ligaments supporting the AA joint:
The cruciate ligament (which is made up of 3 separate ligaments):
- the transverse ligament of the atlas spans the dens horizontally, inserting onto the lateral masses of C1
- the superior and inferior longitudinal bands arise at the transverse ligament, and insert into the occiput and C2 body respectively
The alar ligaments originate from the sides of the dens and insert into the lateral margins of the foramen magnum
The tectorial membrane originates from the body of C2, enters the cranium through the foramen magnum, and inserts into the floor of the posterior cranial fossa. (the tectorial membrane is a superior continuation of the posterior longitudinal ligament)
Describe the uncinate joints
These are present at the level of C3-C6 only, and are also called the joints of Luschka.
These are not a true joint.
They are an articulation between the uncinate process at the lateral margins of the IVDs on the vertebral bodies, with the body of the vertebrae immediately superior to it.
These joints reinforce the cervical spine, create additional stability in the cervical spine for supporting the weight of the skull, and act to prevent excessive lateral translation of the cervical vertebrae relative to adjacent vertebrae, which would compromise the neurovascular structures linking the brain to the trunk.
Which ligaments support the joints of the cervical spine?
There are 7 ligaments that support the cervical spine.
Anterior Longitudinal Ligament
- runs vertically along the anterior surface of vertebral bodies
- from the sacrum to the anterior tubercle of C1 and the occiput
- the only ligament to resist excessive extension
Posterior Longitudinal Ligament
- runs vertically along the inside of the vertebral canal, on the anterior surface of the canal and the posterior surface of the vertebral bodies
- from the sacrum
- broadens to become the tectorial membrane superiorly at the level of the AA joint
- enters the cranium through the foramen magnum and inserts into the floor of the posterior cranial fossa at the occipital bone
- resists excessive flexion
- reinforces IVDs posteriorly and resists the posterior displacement of IVDs
Intertransverse Ligament
- runs vertically between the transverse processes of adjacent ligaments
- resists excessive lateral flexion
Interspinous Ligament
- runs vertically between the spinous processes of adjacent vertebrae, deep to the supraspinous ligament.
- relatively weak
- resists excessive flexion
Supraspinous Ligament
- runs vertically between the tips of the spinous processes of adjacent vertebrae, superficial to the interspinous ligaments
- between C7 - sacrum (becomes nuchal ligament superiorly)
- much stronger than the interspinous ligaments
- resists excessive flexion
Ligamentum flavum
- runs obliquely between the lamina of adjacent laminae, along the posterior surface of the vertebral canal posterior to the spinal cord
- stabilizes the vertebral column
- resists excessive flexion
- reinforces the IVDs postero-laterally
Nuchal ligament
- a thick triangular membrane present in the cervical spine only
- superior extension of the supraspinous ligament above the level of C7
- from SPs of cervical vertebrae to EOP and EO crest of occiput
- reinforces the cervical spine and assists the spine with bearing the weight of the skull
- resists excessive flexion
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Which ligaments act to resist excessive extension of the cervical spine, and which act to resist excessive flexion?
The anterior longitudinal ligament is the only ligament to resist excessive extension of the cervical spine - the structure of the vertebrae and the spinous processes create a bony limit to excessive extension.
There are 5 ligaments that resist excessive flexion - the posterior longitudinal ligament, the ligamentum flavum, the interspinous ligament, and the supraspinous ligament (which becomes the nuchal ligament above the C7 level).
Describe the cruciate ligament of the AA joint
The cruciate ligament is made up of 3 separate ligaments:
the transverse ligament of the atlas, which spans the dens horizontally and holds it in place against the anterior arch of the atlas. This ligament has its insertions on the lateral masses of the atlas.
The superior longitudinal ligament originates from the transverse ligament of the atlas, and inserts into the occiput.
The inferior longitudinal ligament originates from the transverse ligament of the atlas, and inserts into the body of C2.
Describe the nuchal ligament
The nuchal ligament is a superior continuation and extension of the supraspinous ligament at the level of C7 and above.
The nuchal ligament originates from the spinous processes of the cervical vertebrae, and attaches to the external occipital protruberance and external occipital crest of the cranium.
It is a thick triangular membrane present in the cervical spine only.
Its functions are to reinforce and support the cervical spine, and to resist excessive flexion of the cervical spine including counteracting the anteriorly balanced weight of the cranium on top of the cervical spine.
