Cervical Spine - LateralThis is a featured page

,

Radiographic Positioning


Adult
Other related pages of interest

Name of projection Cervical Spine - Lateral supine or erect
Area Covered The cervical spine from C1 down to the C7-T1 joint space and approximately one-third of T1 the first thoracic vertebra
Pathology shown Disruption to the 5 lines of stability, indicating possible fracture, arthritis
Radiographic Anatomy Cervical Spine Radiographic Anatomy
IR Size & Orientation 24cm X 30cm
Portrait
Film / Screen Combination Regular
(CR and DR as recommended by manufacturer)
Bucky / Grid Moving or Stationary Grid
Filter Can be used when using film
Exposure 70 kVp
20 mAs
FFD / SID 180 cm
This larger distance helps overcome the OID (object to image receptor distance) to reduce magnification and improve the sharpness of the image.
Central Ray Directed to the level of C4
Perpendicular to the IR
If the patient has torticollis, a wry neck, then direct the central ray to the inner, concave side to use the diverging rays to help penetrate the intervertebral joint spaces
Collimation Centre: C4
Shutter A: Open to include the top of the ear superiorly
Shutter B: Open to include the soft tissue of the neck anteriorly
The collimation may be angled to match the slope of the neck. For example, when the patient stands, C1 is usually more anterior than C7, so the collimation square may be tilted to match this slope.
Markers Anterior to Cervical Spine clear of perivertebral soft tissues
Marker orientation AP
Shielding Gonadal (check your department's policy guidelines)
Respiration Suspended respiration on expiration.
The shoulders are able to relax downwards on expiration which will maximise the chances of being able to visualise the C7-T1 junction on the image.
Positioning Ensure the removal of artefacts that may superimpose the anatomy of interest, such as earrings and other jewellery

If the patient is erect,
  • The patient is side on to the bucky/IR (usually left side is closest to the IR, however if the patient has torticollis, a wry neck, then direct the central ray to the inner, concave side)
  • Position the midsagittal plane so that it is parallel to the IR
  • Position the interpupillary line so that it is perpendicular to the IR (in an erect patient, this will also be parallel to the floor)
  • Raise the chin slighlty, so that the mandible does not superimposed the cervical spine
If the patient is supine,
  • Position the patient so that the bucky/IR is along one side (usually the left side is closest to the IR)
  • Position the midsagittal plane so that it is parallel to the IR. If the patient is on a barouche, then this is easily achieved by moving the bed.
  • Position the interpupillary line so that it is perpendicular to the IR
  • Only raise the chin slightly if the possibility of spinal injury has been ruled out, so that the mandible does not superimpose over the cervical spine
  • Traction on arms may be required to see T1
Where possible ask the patient to relax their shoulders down and move their finger tips in the direction of their toes on expiration, so that as you expose you have the best chance of penetrating the lower cervical spine area
Critique

Positioning
  • No rotation is evidenced by
    • The posterior vertebral bodies are superimposed (see notes below)
    • The zygopophyseal joints are seen open
  • No tilt is evidenced by
    • The intervertebral disc spaces of the cervical spine are all open (see notes below)
  • No superimposition of the mandible over the cervical spine

Area Covered
  • All of the cervical vertebrae are shown, including spinous processes and the C7-T1 joint space and 1/3 of T1. Also the anterior soft tissue of the neck and airway are seen.
Collimation
  • Centre: C4
  • Shutter A: Open to show the EAMs superioly and the C7-T1 joint space and 1/3 of T1 inferiorly
  • Shutter B: Open to show the soft tissue of the neck anteriorly, and the spinous processes of the cervical spine posteriorly

Exposure
  • Sufficient contrast and density to show the anterior soft tissue of the neck, including the airway.
  • Minimal patient motion and sufficient contrast and density to show sharp, clear cortical margins and bony trabecular markings of the cervical vertebrae
Special Notes The 5 lines of stability
1. Prevertebral (anterior) soft tissue
2. Anterior vertebral bodies
3. Posterior vertebral bodies
4. Spino-lamina line
5. Tips of spinous processes
One line of disruption indicates a stable fracture
Two or more lines of disruption indicate an unstable fracture

Determining the direction of rotation
The posterior vertebral bodies should be superimposed. If this is not the case, to determine the direction of rotation first identify which posterior vertebral body is magnified. This is the side that is furthest from the IR. You can then use this information to correct the positioning.
For example, assume the patient is positioned so that the left side is closest to the IR/bucky and the posterior vertebral bodies are not superimposed. The left margin of the posterior vertebral body is sharper and less magnified, as it is closer to the IR. The right margin is further away and posterior. Therefore, correct the patient's position, bring the right side of the patient forward until the midsagittal plane is parallel to the IR/bucky.

Intervertebral disc spaces
Providing there is no pathology, with good positioning, the intervertebral disc spaces should be
  • open all the way down, from C1 through to C7/T1
  • open across the vertebral body from anterior to posterior
If not, check the position of the
  • midsagittal plane
  • interpupillary line
  • central ray, especially where there is torticollis



AndyC
AndyC
Latest page update: made by AndyC , Jun 4 2011, 10:59 PM EDT (about this update About This Update AndyC Edited by AndyC

22 words added

view changes

- complete history)
More Info: links to this page
Started By Thread Subject Replies Last Post
PeterGleeson Collimate to exclude the thyroid 0 Oct 15 2014, 11:20 PM EDT by PeterGleeson
Thread started: Oct 15 2014, 11:20 PM EDT  Watch
There is no valid reason to irradiate the thyroid. Just before exposure, lean the patient forward so the collimation is 2cm inside the skin edge.
Do you find this valuable?    
Showing 1 of 1 threads for this page

Related Content

  (what's this?Related ContentThanks to keyword tags, links to related pages and threads are added to the bottom of your pages. Up to 15 links are shown, determined by matching tags and by how recently the content was updated; keeping the most current at the top. Share your feedback on WikiFoundry Central.)