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.
If the lateral does not cover to T1 a swimmers view is added to the serie. WH does not routinely do swimmer's views but relies on long obliques (to cover well below C-T junction). Either approach is acceptable.

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.

The lowermost extent of C spine showed on the lateral film is determined. If this is not to T1, the two obliques and/or swimmers views are assessed. Overlap between swimmers and lateral views needs to be confirmed unambiguosly (either C2 shown on swimmers or from unequivocal vertebral morphology identification).

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).

1,2,3,5 are most reliable for disruption. 6 is important for prevertebral hematoma detection.
Disruption to each of these lines can be either an angulation or a displacement (step). As a rule, small steps may be produced by degenerative change and are of uncertain significance if other signs of degenerative disease are present at that level.
Grafic 2.1 shows the outlines of the spinal channel in several types of injury. These Outlines are represented by the posterior vertebral line and the anterior margin of the spinous processes.

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:

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.

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.
Abnormatlities as above.

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

widened soft tissue stripe,
abnormally shaped soft tissue stripe,
air in soft tissue stripe.
Nasogastric and particularly endotracheal tubes invalidate findings.

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

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Because english is not the native language of the authors, we apologize for any inconvenience.

© 1998 by Matthias Kraft & Gesine Schröter;
EMail to: M.Kraft@fhtw-berlin.de & g.schroeter@fhtw-berlin.de
Last changed: Sunday, 08-Feb-2009 12:42:19 CET