11.1 Cervical Spine

11.1 Cervical Spine

Quick Answer: A diagnostic cervical series starts with a true lateral that includes C1 through C7–T1, an AP axial through C4 with cephalad angulation, and an open-mouth odontoid that shows the dens and symmetric C1 lateral masses. Use obliques for foramina, swimmer’s when C7–T1 is hidden, and horizontal-beam lateral first in trauma—never flex, extend, or remove the collar until the spine is cleared. Match geometry to the clinical question so RTR.4 procedures support RTR.6 acceptance decisions.

General radiography — skeletal (spine) is a high-weight clinical procedure area on the CAMRT Radiological Technology blueprint. Cervical examinations are frequent, high-stakes, and rich in critique stems: incomplete coverage of C7–T1, rotated open-mouth views, wrong oblique side, and unsafe motion in trauma all appear as application items. This section builds procedure competence you will reuse for thoracic and lumbar work and for trauma adaptations later in the guide.

Relational Anatomy Essentials

Landmarks for centering and collimation: mastoid tip / EAM, gonion, thyroid cartilage (~C4–C5), vertebral prominens (C7), and the jugular notch as a rough T2–T3 reference when swimmer’s geometry is needed.

Shared Cervical Technique Principles

• SID: Lateral cervical often uses ~180 cm (72 in) to reduce magnification and improve geometric sharpness of the neck; AP and open-mouth commonly use ~100–115 cm (40–44 in) at the upright or table Bucky—follow department charts.
• Grid: Adult neck thickness usually warrants a grid for AP/lateral Bucky work; small pediatrics may be non-grid per protocol.
• Collimation: Skin margins of the neck; include base of skull through upper thoracic transition as required by the projection—do not open to the entire chest “for insurance.”
• Respiration: Suspended expiration for lateral often drops the shoulders slightly; open-mouth may use a soft “ah” to drop the tongue; AP axial typically suspended respiration.
• Immobilization & care: Support the head; never drag a suspected unstable neck. Explain each step; pain and anxiety are high.
• Markers & annotations: Correct laterality; note trauma, collar on, horizontal beam, flexion/extension only when applicable.

AP Axial Cervical Spine

Evaluation criteria: Spinous processes centered in the midline (rotation check); mandibular angles and mastoids roughly symmetric; intervertebral spaces open (correct cephalad angle); C3–C7 vertebral bodies demonstrated without excessive mandibular superimposition. Insufficient cephalad angle closes disk spaces; rotation shifts spinous processes off midline and can mimic pathology.

Why the angle? The cervical bodies and disk spaces are naturally lordotic; a cephalad CR parallels those spaces so they appear open rather than foreshortened.

Open-Mouth (AP) Odontoid Projection

Evaluation criteria: Dens free of superimposition by teeth or base of skull; equal spaces between lateral masses of C1 and dens; symmetric C1–C2 joint spaces; spinous process of C2 midline if visualized. If teeth obscure the dens, adjust head extension or CR slightly; if base of skull obscures the dens, adjust flexion/extension the opposite way—classic critique logic on exams.

Trauma note: Some departments substitute Fuchs (AP) or Judd (PA) for dens when the mouth cannot open, or move quickly to CT. Know that open-mouth quality failures are common and that you must not force jaw motion after facial trauma.

Lateral Cervical Spine

The lateral is often the most important single radiograph for cervical trauma screening in general radiography pathways still using plain film before or alongside CT.

Evaluation criteria:

If C7–T1 is not demonstrated, do not “accept and hope”—obtain a swimmer’s lateral or other department-approved method, or escalate imaging pathway per protocol. Missing the cervicothoracic junction is a classic miss zone for injury.

Oblique Cervical Spine — Anterior vs Posterior

Obliques demonstrate intervertebral foramina and pedicles. Naming confusion is a high-yield exam trap.

Memory aid: Anterior obliques show the downside foramina (the side closest to the IR). Posterior obliques show the upside foramina. Many Canadian departments prefer anterior (RAO/LAO) upright obliques for thyroid dose and positioning comfort—know your site protocol and still be able to interpret either naming system on the exam.

Critique: Closed foramina mean wrong rotation or wrong CR angle. Demonstrating the wrong side relative to the requisition is a procedural error even if the image “looks pretty.”

Swimmer’s Lateral (Cervicothoracic / Twining)

Use when the routine lateral fails at the cervicothoracic junction. In trauma, coordinate with the care team so arm movement does not violate spinal precautions; alternative imaging (CT) may supersede repeated attempts.

Flexion and Extension Laterals

Only when specifically ordered and the cervical spine is cleared for motion by the appropriate practitioner (or when the requisition is explicitly for functional stability assessment under that clearance).

Hard rules: Do not coach forced range of motion in uncleared trauma, rheumatoid instability without orders, or severe pain with neurologic symptoms—stop and escalate. Document patient effort and limitations. These are not part of a default trauma cervical series.

Trauma Horizontal-Beam Lateral — First Principles

1. Do not remove the cervical collar until a qualified practitioner orders removal after clearance pathway.
2. Obtain a cross-table lateral with horizontal CR; IR beside the neck; MSP vertical; no rotation if possible.
3. Include C1 through C7–T1; if not, swimmer’s or CT per protocol—do not sit the patient up for a “pretty” upright lateral first.
4. Minimize log-roll and manipulation; use team lift techniques taught in care-provider competencies.
5. Critique immediately for coverage and gross alignment; communicate critical findings per facility critical-result policy without diagnosing beyond your role.

Portable trauma laterals often use shorter SID and grid challenges—align carefully, annotate horizontal beam and collar status, and accept that CT is frequently preferred for comprehensive trauma clearance while plain-film skills remain exam-relevant.

High-Yield Cervical Injuries (Awareness for Positioning & Critique)

On CAMRT-style stems, link positioning deficiency to missed anatomy: a lateral that stops at C6 can hide clay-shoveler’s or C7 facet injury; a rotated open-mouth can mimic Jefferson overhang; coaching flexion before clearance can convert a stable situation into a cord emergency.

Positioning Summary Table — Cervical Spine

Bottom Line for RTR.4 Cervical Work

Produce a lateral that truly reaches C7–T1, an AP axial that opens mid-cervical disks, and an open-mouth that frees the dens with symmetric C1–C2 relationships. Use obliques deliberately for the correct foramina side, add swimmer’s when shoulders win the superimposition battle, and treat trauma as horizontal-beam lateral first, collar on, no forced motion. Flexion/extension is a specialty add-on after clearance—not a routine trauma step. That procedure judgment is exactly what high-weight skeletal gen-rad items test on the CAMRT exam.