Cervical Spine Flashcards
How many cervical vertebrae are there?
7.
What other name is given to C1?
What other name is given to C2?
How is C7 different from other cervical vertebrae?
Atlas.
Axis.
C7 has a set of spinal nerves above (C7) and below it (C8), therefore there are 8 spinal nerves assoicated with the cervical spine.
What are the characteristic features of the cervical vertebrae?
1) Triangular vertebral body
2) Approximate 1:1 body size:foramen size
3) Bifid spinous process - not present on all vertebrae
4) Transverse foramina - vertebral arteries pass through here.
Joints involving the Atlas, Axis and Cranium
Articulations and joints? Type of Synovial joint?
1) Atlanto-occiptal joints (x2) - superior facets of the lateral masses of the C1 and occipital condyles at the base of the cranium.
Type of synovial joint: Condyloid
Movement: Flexion of the head (nodding)
2) Medial-atlanto-axial joint - dens of C2 and the articular facet of C1.
Type of synovial joint: Pivot
Movement: Rotation (look left and right)
3) Lateral atlanto-axial joints (x2) - inferior facets of lateral masses of C1 and superior facets of C2.
Type of synovial joint: Planar
Movement: Rotation
Atlas
Unique characteristics?
No vertebral body
No spinous process
Lateral masses that are connected by an anterior and posterior arch.
The anterior arch contains a facet for articulation with the dens of C2. This is secured by the transverse ligament of the atlas.
On the superior and inferior aspects of the lateral masses are articular facets.
Axis
Unique characteristics?
Identifiable due to the dens (odontoid process), which extends superiorly from the anterior aspect of the vertebra.
This articulates with the anterior arch of C1, forming the medial atlanto-axial joint.
It also has two superior articular facets that articulate with the inferior articular facets of C1 to form the lateral atlanto-axial joints.
Ligaments unique to the cervical spine?
1) Nuchal ligament - attaches to the tips of the spinous processes - provides attachment for the rhomboids and trapezius.
2) Transverse ligament of the atlas - connects the lateral masses of the atlas, and in doing so anchors the dens in place.
Clinical relevance: Jefferson fracture of the atlas
Aetiology?
Caused by a verticle fall on an extended neck, for example, diving into excessively shallow water.
This results in the lateral masses compressing against the occipital condyles, driving them apart, fracturing one or both anterior/posterior arches.
The transverse ligament may also rupture with enough force.
Unlike to damage to the spinal cord at the level of C1 (as the foramen is quite large), however there could be damage further down the vertebral column.
Clinical relevance: Hyperextension (whiplash) injury
This can be caused by a rear-end traffic collision or poorly performed rugby tackle can result in whiplash.
In minor cases, the anterior longitudinal ligament may be damaged, which can be acutely painful for the patient.
In severe cases, there could be fracture of the vertebrae without involvement of the spinal cord.
Worst case scenario is where there is subluxation or dislocation of the cervical vertebrae. This often happens at the level of C2, where the body of C2 will move anteriorly with respect to C3. This type of injury could involve the spinal cord, and may led to quadriplegia, or death. More commonly, subluxation occurs at C6/C7 (50% of cases).
Clinical relevance: Hangman’s fracture
This refers to the fracture of pars interarticularis (bony column between the superior and inferior articular facets of the axis). Commonly happens due to high velocity hyperextension and distraction of the head.
Such an injury is likely to be lethal as there is likely to be spinal cord rupture, causing deep unconscious, respiratory or cardiac failure.
Clinical relevance: Fracture of the dens
These represent about 40% of C2 fractures.
These fractures are unstable and are at high risk of avascular necrosis, due to isolation of the distal fragment of any blood supply. As with any fracture of the spinal cord, there is a risk of spinal cord involvement.
