Cx Bones

Question 1

Describe the bones of the cervical spine

Answer 1

There are 7 cervical vertebrae.
C1 (Atlas)
C2 (Axis)
C3-6 (typical)
C7 (transitional)

Question 2

Which joints are present in the cervical spine?

Answer 2

Atlanto-occipital (OA)
Atlanto-axial (AA)

C2-7:

• intervertebral joints
• uncinate joints / joints of Luschka
• facet / zygapophyseal joints (left / right)

Question 3

What are the features of the cervical spinal segment?

Answer 3

The most mobile spinal segment - allows for movement of the head

The smallest of the 24 moveable vertebrae - bodies and IVDs are notably smaller than more inferior vertebrae. This is because the cervical spine bears less bodyweight than more inferior segments.

The alignment of the facets in the cervical spine, approximately half way between the sagittal and transverse planes, allows for a large range of movement in all available movement planes.

Question 4

What are the special features of a typical cervical vertebrae?

Answer 4

• bifid transverse processes
• transverse foramen in TPs for passage of vertebral arteries and accompanying veins
• in C7 this foramen is smaller and transmits the veins only
• bifid spinous processes in the majority of the population (C3-6)
• uncinate processes on anterior vertebral bodies forming the joints of Luschka / uncinate joints
• small round bodies
• large triangular foramen for the passage of the cervical plexus
• the orientation of the facets is approximately halfway between the sagittal and transverse planes. The superior facets are directed superiorly and posteriorly. The inferior facets are directed inferiorly and posteriorly.

Question 5

Describe C7

Answer 5

C7 is a transitional vertebrae between the cervical and thoracic spinal segments, and as such has some features that are more similar to a thoracic vertebrae than the other typical cervical vertebrae.

• larger vertebral body
• smaller transverse foramen in TP - for passage of vertebral veins only (not vertebral artery as in more superior Cx segments)
• SP is longer, more slender, and more inferiorly oriented than the other Cx
• SP is not bifid

Question 6

What is the orientation of the facets in the cervical spine?

Answer 6

In the typical cervical vertebrae, the facets are aligned approximately halfway between the sagittal and transverse planes.

The superior facets are directed posteriorly and superiorly, and the inferior facets are directed posteriorly and inferiorly

Question 7

Describe the C1

Answer 7

The C1 is also known as the atlas, and is the most superior vertebrae in the vertebral column.

The C1 directly articulates with the occipital condyles of the skull at the OA (atlanto-occipital) joint, and with the C2 Axis at the AA (atlanto-axial joint).

The C1 is an atypical vertebrae.
It is a ring like vertebrae formed by an anterior and posterior arch connecting two lateral masses.

On the posterior surface of the anterior arch is a facet for articulation with the dens/odontoid process of C2.

On the lateral masses are the articular facets for articulation with the occipital condyles of the skull. These facets are concave structures allowing for sagittal movements.

The C1 does not have;
vertebral body
vertebral disc (superior or inferior)
spinous processes

Question 8

Describe the C2

Answer 8

The C2 is also called the Axis, and articulates with the C1 Atlas superiorly at the AA joint (axio-atlantal joint). It creates a transition between the C1 superiorly and the typical cervical vertebrae inferiorly.

The C2 creates rotational movement of the head, as C1 and the skull pivot as a unit on the C2 vertebrae. Approximately half of the rotational ROM at the cervical spine (90 degrees total) occurs at the C2 vertebrae.

The C2 has a dens / odontoid process projecting superiorly from its vertebral body, and large articular facets projecting superiorly, for articulation with C1.

It has a large bifid spinous process.