Week 4

Cardinal features of the plain cervical spine

	1 Number and type of films for assessment
	2 Alignment
	3 Bony contours
	4 Craniocervical junction
	5 Disc spaces and facet joint spaces; vertebral spacing
	6 Prevertal soft tissues
	7 Biomechanics of the Cervical Spine

1 Number and type of films for assessment:

The standard C spine series (RMH) consists of:

lateral (LAT) - view toward the side of the cervical spine,

frontal - anterior view on the cervical spine,

peg view - posterior view on the cervical spine,

two obliques.

The C-T junction has to satisfactory demonstrated as well as the craniocervical junction. There are seven cervical vertebrae.
C1 (atlas) and C2 (axis) are atypial;
the remainder(C3 to C7) can be considered typical for this discussion.

2 Alignment:

Alignment criteria are the same for each projection, although not all the projections will show all the lines of alignment.
The following lines are reviewed:

1. posterior vertebral line (line of the posterior longitudinal ligament)
2. anterior vertebral line (line of the anterior longitudinal ligament)
3. spinolaminar line (posterior limit of the canal)
4. spinous process line
5. margins of the articular pillars (left and right pillars each have two margins in each view, but in a good lateral view these overlap and are difficult to tell apart).
6. soft tissue line (prvertebral soft tissue and posterior border of the pharynx/larynx air column).

3 Bony contours:

Each typical vertebra is subdivided into a body, two articular masses and a neural arch (laminae, pedicles, spines). For each the following films are reviewed:

• Lat, AP, obliques (for body):

  superior and inferior endplates,

  anterior and posterior and lateral margins,

  trabecular architecture

• Lat (for articular pillars and neural arches):

  diamond shaped contour of articular masses,

  cortical margins of the laminae (where seen)

  and spinous process)

• AP (for articular pillars and neural arches):

  articular masses overlap;

  cortex of laminae and spinous processes are usually well shown.

• Obliques (for articular pillars and neural arches):

  diamond shaped contour of articular masses,

  side on lamina,

  side on predicle,

  end on lamina,

  end on predicle,

  Usually only the articular pillar clear of the vertebral bodies is well shown,
  and usually the side on lamina is not well seen.

Abnormalities are of three types:

cortical step or discontinuity;

cortical angulation (no step or discontinuity apparent);

abnormal shape but without fracture line apparent.

4 Craniocervical junction:

A special area with its own features.

Alignment:

occipital condyles to C1 lateral masses to C2 masses (may not show well in lateral) - this is both lateral and medial margins. Clivus to odontoid process tip, then lines of alignment as for rest of C spine.

Bony contours:

C1 lateral masses, C1 posterior and anterior arches.

Odontoid process anteroir, posterior and lateral cortices;

lateral masses and shoulders of C2;

laminae and spinous process of C2.

5 Disc spaces and facet joint spaces; vertebral spacing:

Area of most degenerative change, so findings do not always indicate trauma. Disc spaces should be comparable at all levels and of normal height. Facet joint spaces have parallel articular surfaces without subluxation, and are comparable at all levels (except craniocervial junction). In oblique views end on laminae 'shingle'. The interspinous distances (below C2) are comparable leel to level.

Abnormalities (traumatic):

narrowed disc space;

widened disc space, abnormally shaped disc space;

widened interspinous distance narrowed interspinous distance (non postural);

subluxed facet joint, perched facet joint, dislocated facet joint.

6 Prevertebral soft tissues:

Width guidelines exist, but are neither completely sensitive nor completely specific (7mm at C2, 2cm at C7). The soft tissue line should follow the bony contour (i.e. W shaped at the craniocervical junction) down to the level of the larynx, where the esophagus is interposed.
Table 6.1 shows normal prevertebral spaces at the levels from C1 to C7

Abnormalities:

widened soft tissue stripe,

abnormally shaped soft tissue stripe,

air in soft tissue stripe.

7 Biomechanics of the Cervical Spine

Functional division

The cervical spine is functionally differentiated from the remainder of the vertebral column. Its morphology permits wide ranging mobility. It has two normally curves dividing it morphologically and physiologically into upper and lower segments at C2.
The upper cervical segment includes the occiput, atlas (C1) and axis (C2) vertebrae. This is referred to as the craniovertebral region.
The lower segment consists of spinal units from C2 to C7.

Craniovertebral Joints

The craniovertebral region contains the occiput, atlas and axis. This complex is the most complicated series of articulations in the human body. It has to serve as a transition zone between the normal vertebral joint structures and the completely different skull. A lot of different studies have been done to investigate the movement in this region. For our field of interest especially the range of motion is of importance.

Table 7.1 presents the ranges of movement at the atlanto-occipital and the atlantoaxial functional units.
Tables 7.2-4 give the coupled ranges of movement during each of the principal ranges of movement.
Table 7.5 gives representative values of the range of rotation of the craniovertebral complex.

The two bones atlas and axis have a very special structure:
Grafic 7.1 shows to the atlas with inscriptions of its parts
Grafic 7.2 shows to the axis with inscriptions of its parts

Cervical spine (C2 to C7)

The lower cervical spine consisting of functional spinal units from C2 to C7, also participates in the global mobility of the head. Classically, the movements are described as flexion-extension, lateral-flexion and rotation.
It was found that flexion movement causes a slide of the vertebra upward and forward and that downward and backward movement is caused by extending. In recent studies an important relationship between flexion-extension (sagittal plane rotation) and two translations was found. This relationship was found as a linear one depending on the values of two independent variables; cephalocaudat(Y) and ventrodorsal(Z) translation.

Table 7.6 gives the 95 percent confidence interval for the ranges of flexion-extension, ventrodorsal and cephalocaudad translations.
Table 7.7 shows the rotation ranges for the lower vertical spine.

Grafic 7.3 shows the structure of a normal vertebra in cervical spine with inscriptions of its parts