Lab 2, Station 3: Imaging of the Vertebral Column

Lab 2 navigation

Radiography of the Spine

Radiography involves using radiation (x-rays) to provide images of the tissues, organs, and bones, that comprise the human body.

To create a radiograph, a patient is positioned so that the part of the body being imaged is located between an x-ray source and an x-ray detector. When the machine is turned on, x-rays travel through the body and are absorbed in different amounts by different tissues, depending on the radiological density of the tissues they pass through.

For example, bones readily absorb x-rays and therefore appear whiter than other tissues against the black background of a radiograph. Conversely, x-rays travel more easily through less radiologically dense tissues, such as fat, muscle, and air-filled cavities such as the lungs. These structures are displayed in shades of gray on a radiograph.

The vertebral column’s bony composition make x-rays an ideal modality for quick evaluation, such as checking for fractures after mild or moderate trauma.

Altering the way the body is placed relative to the detector creates specified projections (the path the x-ray beams take through the body) that are used to examine structures from different angles.

Some examples of common spinal projections are shown here:

Question

Which projection would provide the best view for evaluating the normal curvatures of the spine? Which view would show evidence of scoliosis?

Lateral Spine Radiographs

Lateral view x-rays are important when:

■Checking for proper alignment of vertebrae and normal spinal curvatures

■Inspecting individual vertebrae for fractures, bone spurs, slippage, etc.

■Assessing intervertebral disc degeneration

Lateral Cervical

Key structures to view in the cervial region:

■Atlas (C1)

■Axis (C2)

*Dens

■C7

Spinous process = vertebra prominens (VP)

Question

Hyper extension of the neck would damage which part of the cervical vertebrae?

Lateral Thoracic

Normal alignment of the thoracic vertebrae creates a slightly kyphotic curvature.

The rib cage can act to stabalize the thoracic spine even in the case of vertebral fractures

Lateral Lumbar

See if you can identify the features of the vertebral column you are learning in the lateral lumbar radiograph shown below.

Figure 2.22.

Question

The notch forming the TOP half of an invertebral foramen is named the INFERIOR vertebral notch. What gives!?

Clinical Examples

The clinical examples shown here,

and in later sections on this page, are to help you see how imaging anatomy can be applied to the clinical setting. You are not expected to know, or be able to identify these at this point in your training.

Figure 2.23. Calcification of the anterior longitudinal ligament.

Figure 2.24. Disc space narrowing at L4/L5.

Figure 2.25. Kyphosis before and after spinal fixation.

Figure 2.26. Fracture of C7 spinous process.

Figure 2.27. Hyperflexion injury with acute angulation at C3/4 (arrow), facet joint subluxation (circle) and interspinous widening (arrow heads).

Figure 2.28. Compression fracture of anterior vertebral body.

Anterior Posterior (AP) Spine Radiographs

The AP designation indicates the x-ray travels from anterior to posterior, with the back of the patient closest to the detector.

In AP radiographs, the spinous processes are seen enface (viewed front on), over lapping the vertebral bodies and intervertebral discs. The pedicles, also visualized enface, project as oval densities on either side of the bodies.

Use the diagrams and complete anatomy link to identify the labeled structures in the AP thoracolumbar radiograph below.

Complete anatomy

AP lumbar spine

Clinical Examples

Oblique Spine Radiographs

Oblique radiographs can be utilized to visualize the spine from additional angles (between AP and lateral). Positioning for oblique radiographs requires rotation at approximately 45 degrees.

The lumbar spine oblique view is used to visualize the articular facets and pars interarticularis of the lumbar spine. Clinicians often refer to the appearance of the lumbar vertebrae in the oblique view as the Scottie dog.

Can you see the resemblance?

Figure 2.36.

Clinical Example

A break appearing in the “neck” of the Scottie dog correlates to a fracture of the pars interarticularis = spondylolysis.

This type of fracture can lead to spondylolisthesis = slippage of one vertebral body relative to an adjacent one.

Sectional Imaging

Radiologic sectional images (CT, MRI) are acquired and displayed according to anatomic planes that pass through the body.

■Sagittal

■Coronal (frontal)

■Axial (transverse)

Figure 2.40. Sagittal Plane

A vertical plane that passes through the body, dividing it into left and right portions.

Sagittal images traditionally are shown as though the patient is looking to the viewer's left.

Figure 2.41. Coronal Plane

A vertical plane that passes through the body, dividing it into anterior and posterior portions.

Coronal images are traditionally shown as though the patient is standing face to face with you.

Figure 2.42. Axial Plane

A horizontal, or transverse plane that passes through the body, dividing it into superior and inferior portions.

Transverse or axial images are presented as if the viewer is standing at the feet end of a supine patient.

Accessing Donor CT Scans on PACS

Inland Imaging has graciously provided you with CT scans for each of the donors you will be working with in lab. You should plan to access your donor scan on a regular basis to practice identifying anatomical structures and to explore the potential pathologies present in your donor.

For this lab, open the CT scan of your donor and practice identifying structures of the vertebral column in each of the three planes. Be sure to note any abnormalities or pathologies you see – these are things you can share during your capstone presentation at the end of the year.

Open PACS ANYWHERE