Spinal Radiography: Cervical, Thoracic, and Lumbar Spine

Spinal Radiography: Cervical, Thoracic, and Lumbar Spine

The spine is one of the most frequently imaged structures in limited-scope practice. Requests come from primary care offices, urgent care centers, and occupational health clinics for complaints ranging from neck pain to low-back injury. Producing diagnostic-quality spinal radiographs requires precise positioning, correct technical factors, and strict attention to patient safety—especially when trauma is a possibility.

Anatomy Review

The vertebral column has five regions. As a limited-scope practitioner you will image three of them routinely:

• Cervical spine (C1–C7): Seven small vertebrae forming the neck. C1 (atlas) and C2 (axis) have unique shapes that require specialized projections.
• Thoracic spine (T1–T12): Twelve vertebrae that articulate with the ribs. Natural kyphosis and overlying rib and lung structures make this region technically challenging.
• Lumbar spine (L1–L5): Five large vertebrae bearing the most body weight. L5 articulates with the sacrum at the lumbosacral junction. The sacroiliac (SI) joints are visible on AP and oblique lumbar views.

Disc spaces—the gaps between vertebral bodies occupied by intervertebral discs—must be open and clearly visualized on a diagnostic image. Collapsed or narrowed disc spaces are clinically significant findings.

Standard Projections

Cervical spine: AP, Lateral (upright), AP Axial (open-mouth odontoid for C1–C2), and bilateral obliques (45°) to show intervertebral foramina. The swimmer's lateral (Twining method) is added when the cervicothoracic junction (C7–T1) is not visible on the standard lateral.

Thoracic spine: AP and Lateral. For the lateral, the patient's arms are raised to move the humeri out of the field. Breathing technique (slow, shallow or orthostatic breathing during a long exposure) blurs overlying rib and lung detail, improving vertebral body visibility on the lateral view.

Lumbar spine: AP, Lateral, and lateral L5–S1 spot. Obliques (45°, RPO/LPO or RAO/LAO) are added when the referring provider requests evaluation of the posterior elements (pars interarticularis—the "Scotty dog" sign).

Positioning and Technical Tips

Central ray and collimation: Collimate closely to the region of interest. For the cervical AP, the CR is directed cephalad (approximately 15–20°) to the level of C4. For the lumbar AP, the CR is perpendicular to the IR at the level of the iliac crest (approximately L4–L5). Always align the CR perpendicular to the disc spaces unless the protocol specifies an angle.

Grid use: Spinal radiography requires a grid. Use the upright wall Bucky for weight-bearing views (preferred for the cervical lateral and lumbar AP/lateral when ordered weight-bearing) and the table Bucky for recumbent positioning.

Breathing instructions: For the thoracic lateral, instruct the patient to breathe slowly and continuously during the exposure (exposure time is set longer for this effect). For all other spinal projections, instruct the patient to suspend respiration on expiration to reduce diaphragm elevation and achieve consistent positioning.

Oblique positioning: Cervical obliques are usually performed PA (RAO/LAO) to reduce dose to the lens of the eye and thyroid. Lumbar obliques are typically AP (RPO/LPO). Rotate the patient to 45° using positioning sponges. Confirm rotation visually and with the positioning aid before exposing.

The Swimmer's Lateral (Twining Method)

When the standard cervical lateral fails to demonstrate C7–T1 due to superimposition of the shoulders, the swimmer's lateral is performed. The patient stands or lies laterally; one arm is raised (elbow flexed, hand near head) and the opposite arm is depressed (pulled toward the feet). The CR enters at the level of C7–T1. Practice this on a mannequin before applying it to a patient. Discuss with your supervisor whether the clinical situation warrants it—this projection is not part of every routine cervical series.

Trauma Precautions: Safety First

If a patient arrives with a history of trauma (fall, motor vehicle collision, sports injury), assume spinal injury is possible until cleared by the supervising clinician.

• Do not remove a cervical collar without explicit clinician instruction.
• Do not move the patient's neck or back beyond what is absolutely necessary to place the IR.
• For a trauma cervical lateral, perform a cross-table lateral first with the patient supine—this is the initial projection in many trauma protocols. Proceed only after the supervising clinician reviews the image.
• Alert your supervisor immediately if the patient reports new or worsening numbness, tingling, or weakness during positioning.
• Use lead markers (R/L) on every image; incorrect side marking on a spinal image can have serious clinical consequences.

Image Evaluation

A diagnostic spinal radiograph must show:

1. All vertebrae in the requested region, with open disc spaces.

2. No motion blur.

3. Appropriate density and contrast—vertebral bodies and posterior elements visible without washing out soft tissue.

4. Correct collimation and anatomic marker.

5. No rotation on AP projections (spinous processes midline, pedicles symmetric).

When reviewing lumbar images, practice identifying L1 through L5 by counting down from T12 (last rib-bearing vertebra) or up from the sacrum. Document your findings in your logbook using the image evaluation rubric provided.