Trauma Radiography Series: The Cervical Spine


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This radiology continuing education article navigates the Radiographer through radiographic imaging of the cervical spine. The rationale for maintaining a high suspicion for spinal cord injury in the trauma patient is clearly discussed. This lesson gives clear explanations of plain film diagnostic imaging criteria, CT protocols, and is truly a treatise in horizontal beam imaging. Upon completion the reader will understand the important concepts in trauma imaging of the cervical spine and maintaining spine precautions throughout all radiographic procedures.
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Author: Joseph, Nicholas
Credits: 2

-- Please note: This article is either under construction or in the approval process. There will be no credit available for this article until the approval process has been completed. Passing the test for this article before the approval process has been completed WILL NOT result in full credit being awarded when the approval process has been completed. You must pass the test for this article after the approval process has been completed in order to receive credit for this article.

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Instructions:

This activity may be available in multiple formats or from different sponsors. ARRT does not allow CE activities such as internet courses, home study programs or directed readings to be repeated for CE credit in the same or any subsequent biennium”

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Objectives

Outline

Introduction

Section 1.1: Spinal Cord Injury

Section 1.2: Anatomy of the Cervical Vertebrae

Section 1.3: Soft Tissue Structures of the Neck

Section 1.4: Plain Film Radiographic Imaging of the Trumatic Cervical Spine

Section 1.5:Trauma Protocols ACEP/ACR

Section 1.6: Case Study: Multi-Radiography approach

Summary and References

Bottom






Objectives:

Upon completion the reader will be able to:
  • Define spinal cord injury.
  • State the incidence of traumatic spine injury.
  • State the proper procedure for logrolling a patient with a suspected spinal cord injury.
  • List the parts of a typical vertebra and state what the distinguishing features of a typical cervical vertebra are.
  • Discuss the importance of soft tissues of the neck in regards to those vessels that supply the brain with blood.
  • List and discuss the two types of joints of the spine, their structure and movements.
  • Discuss the structure of the intervertebral joints and attachments of the longitudinal ligaments that frame them.
  • Discuss the structure and function of the atlas that make it an atypical cervical vertebra and list the joints it forms.
  • State the number of pairs of spinal nerves and their pattern of distribution for exiting the spinal canal.
  • State what structures must be adequately visualized on plain film imaging to accurately diagnose the cervical vertebrae.
  • List the standard minimum radiographic images that should be taken as part of the trauma cervical spine series.
  • State why the lateral plain film radiograph is risky as a total screen for traumatic cervical spine injury.
  • State the proper procedure and CR alignment for trauma imaging of the cervical spine.
  • Discuss why the superior margin of the lateral radiographic view should include the sphenoid sinus for patient that presents with bleeding or CSF from the ear.
  • Name the three contour lines that must be clearly differentiated from the occiput through T1 to be considered a complete diagnostic lateral radiographic image of the cervical spine.
  • State what must be clearly demonstrated on the Swimmer’s view if it is added to evaluate the distal cervical spine.
  • State whether pulling down on the shoulders is an acceptable technique for acute trauma imaging of the cervical spine.
  • State the diagnostic failure rate for trauma spine imaging in the absence of completing the American College of Radiology protocols for spine imaging.
  • State the reported false negative rate for plain film radiographic imaging followed by axial thin cut CT scanning with coronal and sagittal 2D reconstructions.
  • Discuss why complete cervical spine CT imaging with coronal and sagittal 2D reconstruction is the study of choice at many institutions for the unconscious or intubated trauma patient.
  • State the definitive study that will evaluate the effect of a vertebral fracture found by plain film or CT imaging involving potential injury to the cervical spine.
  • State the structures best visualized by the following views: AP, AP odontoid view, Lateral, AP or PA oblique.
  • Discuss the disability associated with spinal cord injury.
  • Discuss the complication, syringomyelia, which affects about 2% of spinal cord patients.


Outline-Trauma Cervical Spine Radiography

Introduction: Raising the standard of trauma care through high suspicion for injury
  1. Spinal cord injury
    1. Spinal cord injury (SCI) defined?
    2. Incidence of spinal cord injuries
    3. Pre-hospital management of potential SCI

  2. Anatomy of the cervical vertebrae
    1. Distinguishing features of cervical vertebrae
    2. Posterior quadrilateral architecture and anterior vertebral architecture
    3. The intervertebral disc
    4. The atypical cervical vertebrae (C1, C2, and C7)
  3. Soft tissue structures of the neck
    1. Fascial planes of the neck
    2. The airway
    3. The vertebral and carotid arteries
    4. Cervical spinal nerves
  4. Plain film radiographic imaging of the traumatic cervical spine.
    1. Trauma crosstable lateral cervical spine view
    2. Horizontal beam lateral Swimmer’s view
    3. The AP cervical spine view
    4. The open mouthed odontoid view
    5. The Fuchs view of the odontoid tip
    6. Orthopantomogram of the atlas/axis
  5. Trauma Protocols: American College of Radiology (ACR) and American College of Emergency Physicians (ACEP)
    1. Radiographic assessment of the unconscious intubated person
    2. Radiographic assessment of a conscious symptomatic patient
    3. Clinical clearance of the cervical spine
    4. Additional studies of the cervical spine
  6. Case Study: Multi-Radiography Approach to Traumatic C-Spine Imaging
    1. Plain films of the C-spine
    2. CT assessment of the C-spine
    3. MRI assessment of the C-spine
    4. Common fractures and injuries of the cervical spine
    5. Disability associated with spinal cord injury.
  7. Summary and References



Introduction


Wilhelm Conrad Roentgen in 1895 discovered "a new kind of ray," which became known as x-rays. Subsequently, development of a still rapidly expanding discipline of radiology began. With the technical achievements that belong to our field, and the specific education of registered radiologic technologists, radiology is fully part of the medical armamentarium. The medical community draws extensively from radiological services, and radiology is especially important to emergency room (ER) physicians. In addition, non radiologist physicians are required in many settings to initially interpret a wide range of radiological studies because they are on the front line of critical patient care. Emergency room physicians request a miscellany of diagnostic test and procedures in their consultations with radiologist. Consider that for each patient seen whether critical or not, the physician must make a decision as to the nature, severity, treatment, and follow-up each requires. In most cases radiologic findings are formulated in consultation with a radiologist; however, often an ER physician must make an initial diagnosis alone. What this means to radiography practice is that the radiographer ought not produce diagnostic images as simple replications of specific views, but must demonstrate the diagnostic criteria pertaining to each image in a study.

Therefore, as radiographer’s, we must know the diagnostic criteria for each image we take, and present it point for point of reference. Nowhere in radiography are the standards for imaging more important than in dealing with traumatic spine injury. This continuing education module applies such a standard to the radiography of the cervical spine following traumatic injury. This module will briefly review the normal anatomy of the cervical spine, present some of the universal recommendations for plain film and CT imaging, and show through radiographs how common it is for cervical spine injury to be present following traumatic injury. It is hoped that the reader will gain an appreciation of trauma imaging that will translate into better radiographic imaging and patient care.





Section 1.1: Spinal Cord Injury


Spinal cord injury (SCI) is an injury to the spinal cord or nerve tracts that relay signals to and from the brain and body. Trauma is the leading cause of spinal cord injury and is caused most commonly by motor vehicle accidents. Falls and violent acts account for the second leading causes of spinal cord injury. Traumatic spine injury occurs in approximately 1 in 10,000 individuals per year; most are males in their teens or twenties. Greater than half of cord injuries occur in the cervical spine region, a third in the thoracic region, and the remainder in the lumbosacral area. Paramount to vertebrae injury is the question of neurological injury. Most cases of spine injury do not involve permanent cord injury. The standard of medical care demands a high index of suspicion of injury in certain type types of trauma. This means that in certain types of trauma the safest medical strategy is to assume an unstable fracture or dislocation of the vertebrae exists until proven otherwise. This point of view must be part of the working assumption of the entire medical team providing care to a trauma patient. As part of the medical team continuum of patient care, the radiographer must also assume spine injury until proven otherwise.

The management of a patient with a potential spinal cord injury begins in the pre-hospital environment under the care of paramedics. They are specially trained to identify common situations in which a spinal cord injury is likely to occur and correctly immobilize the patient. Ideally, the patient is immobilized in the neutral position on a full spine board with a combination of a cervical collar, side head supports, and strapping of the shoulders and pelvis so that the neck is not the center of the body's rotation. The spine is protected at all times during transport because it is not the center of the body's rotation should the patient move involuntarily. Sandbags and a cervical collar alone do not provide maximum protection when moving the patient, the shoulders and pelvis must be strapped to the board also. When the patient is moved to a gurney or x-ray table the spine must stay in alignment and not be rotated. The rule for protecting the spine from further injury is to immobilize it. These precautions are the standard of care for handling a trauma patient suspected of spine injury.

Once the patient arrives in the hospital trauma suite, the patient may be removed from the spine board to a rigid transfer board. Logrolling the patient is the standard maneuver for any movement of the patient. This transfer process allows physical evaluation of the back (alignment of the spinous processes), rectum for bleeding, and other data. Under no circumstance should the log-roll technique be short changed by too few movers. The radiographer should not participate in the logroll procedure unless properly trained. If a transfer from the spine board is done it must be accomplished under the direct guidance of the trauma physician(s). The process can use nursing, emergency medical technicians (EMT), and providers from the trauma team. To properly logroll the patient there must be at least two persons on each side of the patient, and one at the head end to support the neck. The procedure should be smooth, and the entire spine kept in alignment during the movement.

To help understand the severity of spinal cord injuries and the radiographer's role in providing diagnostic images of the spine, a brief review of the structure of the vertebrae and spinal cord is essential. In this module we will explore current imaging standards and recommended imaging protocols for radiographic examination of the cervical spine and its spinal cord segments in critically injured patients. Although institutions vary in the type and functionality of radiographic equipment, trauma imaging standards can be completed using any available equipment. The key to a good radiography department’s response to trauma is the education of the technologists dealing with trauma. By remaining updated in current radiographic imaging standards the technologist is armed with the understanding of what it is to have a high suspicion for injury that translates into safe quality patient care.





Section 1.2: Anatomy of the Cervical Vertebrae

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The two radiographs above are sagittal images of the cervical spine reconstructed from axial slice data. The CT image (left) demonstrates the bony anatomy, and the MR image (right) demonstrates soft tissue structures of the spine.

There are seven cervical vertebrae that are numbered from top to bottom (C1, C2, C3, C4, C5, C6, and C7). They are conveniently labeled as typical or atypical according to their anatomical features. The typical cervical vertebrae have the following parts: a vertebral body, two pedicles, two lamina, and a single spinous process, two transverse processes, two inferior, and two superior articular processes. Vertebrae three through six are typical cervical vertebrae. The first, second, and seventh cervical vertebrae are atypical. Regardless of whether a vertebra is typical or atypical there are some features shared by all cervical vertebrae that distinguish them from other vertebrae like the thoracic, lumbar, or sacral vertebrae.

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Lateral radiograph (above) of the cervical region of the vertebral column in which the bodies of the cervical vertebrae (1 through 7) are numbered.

Cervical vertebrae have relatively small vertebral bodies that get progressively larger from top to bottom in order to bear the weight of the skull. The distinguishing characteristics of a cervical vertebra are: a triangular vertebral foramen, bifid spinous process, and the lateral margin of each transverse process end as two tubercles with a groove between them. However, the most distinguishing feature of a cervical vertebra is the presence of a transverse foramen in each transverse process (white arrows in pictures below).

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The picture above is an axial CT thin cut through a cervical vertebra presented in a bone algorithm. The white arrows point to the transverse processes and transverse foramina.

Typical Cervical Vertebrae (C3-C6)

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The axial CT image above (right) demonstrates some of the parts of a typical cervical vertebra, which are cervical vertebrae 3 through 6. The 3D reconstruction from axial CT images demonstrates the lamina and spinous processes.

A typical vertebra is conventionally divided into two parts: a large anterior portion called the body and posterior to it the vertebral arch. The body bares the weight of the trunk, whilst the arch protects the spinal cord and its associated nerve roots. The vertebral arch is formed by two pedicles that extend from the posterolateral portion of the vertebral body joining the two laminae to make up the posterior bony ring. The posterior portions of the vertebral body along with its bony arch form a large foramen called the vertebral foramen. Successive stacking of the vertebral foramina forms a bony tube, called the vertebral canal, which encloses the spinal cord and its meninges. On each side of the vertebral arch, projecting laterally from the union of the pedicle and lamina is a transverse process. Extending posteriorly from the junction of the laminae is a single spinous process. The transverse processes and spinous process act as levers to which muscles attach to effect movement of the spine.

Also arising from the arch are four processes called zygapophyses that participate in forming joints of the spine. Two project superiorly and two inferiorly and are so named the superior and inferior articular processes. Each process bares a facet for articulation with an adjacent vertebra’s zygapophyses. The zygapophyses form joints called apophyseal joints. These articular surfaces are where joint movements of the spine occur.

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The picture above is an axial CT slice of the first cervical vertebra. The superior articular processes are well demonstrated in this view. The superior processes face backward and the inferior processes face forward on the 3rd through 7th cervical vertebrae.

Articulations of superior articular processes of one vertebra and the inferior articular processes of an adjacent vertebra form a joint termed an apophyseal joint. Each articular process bares a facet, which is a smooth area on the bone where joint articulation takes place. Each vertebra articulates with an adjacent vertebra above it and the vertebra below it to share four apophyseal joints, two above and two below. These joints are classified as diarthroses or synovial joints. Synovial joints provide free movement between the bones they join. They have an articular cartilage membrane surrounding a joint cavity. Within the membrane bound space is synovial fluid that reduces friction between the bones. In the spine these joints are capable of flexion, extension, lateral bending, and rotational movements.

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The picture above is of a region of a lateral cervical spine radiograph. The apophyseal joints formed by the inferior and superior articular processes are superimposed.

The posterior quadrilateral architecture and anterior vertebral architecture

Along with the apophyseal joints, the posterior quadrilateral architecture of each vertebra is anatomically important. This area encompasses those structures from the posterior boundary of the vertebral body to the spinous process. Its bony structures include the pedicles, laminae, superior articular processes, and inferior articular processes. The posterior quadrilateral architecture describes those structures that form the vertebral foramen as viewed on a lateral radiograph of the cervical spine.

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The picture above of a lateral radiograph demonstrates the posterior quadrilateral architecture, which are the apophyseal joints and vertebral arch structures. The white lines in the picture below outline the quadrilateral bony architecture.
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The reason the posterior architecture is so important radiographically is that it involves structures that surround the spinal cord. A fracture involving the vertebral foramen could damage the spinal cord causing significant consequences for the patient. It is crucial to cervical spine imaging that the entire quadrilateral architecture is demonstrated for all cervical vertebrae and the first thoracic vertebra.

The anterior architecture of the vertebra consists of the vertebral body for typical vertebrae and for atypical vertebrae C2 and C7. The boundary for the anterior architecture is the posterior and anterior contour lines. Structures to be found between these two lines are the vertebral bodies, intervertebral disc, and ligaments that support the spine. Now we can look at the gross anatomy of the cervical spine as regions whose boundaries are formed by the anterior contour line, posterior contour line, and laminospinal line.

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The pictures above and below of lateral radiographs demonstrates the three contour lines used to localize the anatomy of the cervical spine. The posterior architecture is seen in the picture above delimited by the laminospinal lines (A), and the posterior contour line (B).
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Above, the anterior architecture is delimited by the anterior and posterior contour lines. The radiographer should be familiar with these conventional anatomical boundaries since they must be demonstrated through all cervical vertebrae.

The intervertebral disc

The intervertebral discs are interposed between adjacent vertebral bodies placing them within the boundaries of the anterior architecture of the spine. The structure of an intervertebral disc consists of concentric outer rings of fibrous tissue called the annulus fibrosus. The annulus fibrosus provides the strongest attachment affixing vertebrae together. The center of the disc is a fluid moiety called the nucleus pulposus. It hydrostatically maintains the height of the vertebral column. The intervertebral disc is classified as a symphyses joint, which affords slight movement.

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The MR image above is a sagittal reconstruction from axial images. The fluid moiety (nucleus pulposus) in the center of the intervertebral disc is seen. Surrounding the nucleus is a dark band that is the annulus fibrosus. Notice how the annulus is tightly bound to the vertebral bodies holding them together, whilst the liquid moiety maintains the height of the space between the bodies. Also notice how the anterior and posterior longitudinal ligaments are firmly attached to the bodies and intervertebral discs (see drawing and radiograph).

Anterior to the discs and vertebral bodies is a tightly bound anterior longitudinal ligament. It extends from the anterior surface of the sacrum to the anterior tubercle of the atlas and portions of the skull. Its role is to limit hyperextension of the vertebral column. The posterior longitudinal ligament is firmly fixed to the posterior periosteum of the vertebral bodies and intervertebral discs. It runs from the sacrum to the atlas and is within the vertebral canal. It functions to limit hyperflexion of the vertebral column.


Atypical Cervical Vertebrae C1 (atlas), C2 (axis), and C7 (vertebra prominens)

Three of the cervical vertebrae are classified as atypical. These are the first cervical vertebra called the atlas, the second cervical vertebra called the axis, and the seventh cervical vertebra called the vertebra prominens.

The Atlas

The first cervical vertebra is called the atlas because it articulates superiorly with the base of the skull, and bares its weigh. The atlas is atypical because it lacks pedicles, laminae, and spinous process. Instead it has an anterior and a posterior arch. Two large lateral masses lie between the arches having on their superior and inferior surfaces the four articular processes and their facets. The picture below demonstrates the two large superior articular processes, one on each lateral mass, which through their facets articulate with the occipital condyles on the skull base.

The Atlas

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Above is a CT axial cut through the atlas (left), and diagram of the same (right). The large lateral masses and their superior articular processes are seen. They are connected by an anterior and a posterior arch. The atlas does not have a vertebral body, pedicles, laminae, or a spinous process, which makes it atypical.

The superior articular processes and occipital condyles form two joints called the atlantooccipital joints. These joints provide flexion and extension movements between the neck and skull such as in motioning “yes” by nodding of one's head (see radiograph below and arrows).

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The radiograph above (lateral view) of the upper cervical spine demonstrates the atlantooccipital joints formed by the condyles of the occipital bone and the superior articular processes of the atlas. The arrows point to the atlantooccipital joints which are superimposed on the lateral view.
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The pictures above are reconstructed CT images from axial CT data. The coronal image (left) demonstrates the normal position of the two atlantooccipital joints (blue arrows). The sagittal view (right)is shown to demonstrate the relationship between the superior articular processes of the atlas and the occipital condyles that sit in the concave grooved formed by the lateral mass (white arrows).

The Axis (C2)

The second cervical vertebra is also atypical in that the body of the vertebra is expanded bearing a tooth like process called the odontoid process (dens). It is the strongest of the cervical vertebrae. It possesses large superior articular processes for articulation with the atlas that rests upon them. Its parts are a bifid spinous process, inferior articular processes, superior articular processes, transverse processes and transverse foramina, pedicles, and a vertebral body that bares an expanded tooth-like process called the odontoid process.

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The drawing above (left) exhibits the parts of the second cervical vertebra called the axis. The radiographic image on the right (above) is a 3D reconstruction from axial data. It shows the surface structure of the axis from the posterior view.

The superior articular processes of the axis, along with the two inferior articular processes of the atlas, form two atlantoaxial joints. A transverse ligament holds the odontoid peg of C2 in place against a facet on the posterior wall of the anterior arch of C1. These joints are functionally important because this is where the atlas and skull and rotate as a unit upon the axis. It is a side-to-side rotation as in disapproval nodding, which is contraindicated in acute head and neck trauma because such movement can cause spinal cord injury if certain types of traumatic fracture(s) involving the cervical vertebrae are present.

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The drawing above (right) and lateral radiograph (left) demonstrates the odontoid process of C2 which articulates with the anterior tubercle and transverse ligament of the atlas.

The atlantoaxial joints are also radiographically important, therefore, the radiographer should understand their relationship to normal anatomical function. These joints are aligned like all vertebrae along the lateral margins. Because these joints are diarthrodial joints, they are spaced between the articular processes by a synovial membrane and synovial fluid. Therefore, they should have a spacing that reflects this anatomy.

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The pictures above are of a linear tomogram through C1/C2. On the left the image is labeled and on the right the image is unlabeled to demonstrate a clear view of the atlantoaxial joints and odontoid process.

Vertebra prominens (C7)

The seventh cervical vertebra is considered an atypical cervical vertebra because of its long spinous process that can be seen and felt in the back of the neck. Also, it has long transverse processes resembling a thoracic vertebra, but is distinguished by the absence of rib attachment. The vertebral arteries do not pass through the transverse foramen of the seventh cervical vertebra. Therefore the atypical vertebrae are C1, C2, and C7.






Section 1.3 Soft Tissue Structures of the Neck

The seasoned radiographer knows that the soft tissue structures of the neck are just as important as the bony spine. This is especially true when we consider trauma imaging. The potential for soft tissue injury from penetrating trauma, blunt trauma, forces associated with motor vehicle accident, and other types of trauma heighten the risk for soft tissue injury. By soft tissue structures we imply that in addition to the bony spine, all tissues within the boundaries delimited by skin (anteriorly, posteriorly, and laterally). These tissues include muscles, fat, the airway, esophagus, blood vessels, and the like. For our study we will only consider the airway and the carotid and vertebral arteries.

The airway is important to trauma because it must be maintained as part of the ABCs of survival (airway, breathing, and circulation). Radiographically, the injury to the airway or retropharyngeal space may indicate substantial trauma. Any deviation of the airway and other soft tissue structures may indicate a need for acute emergency treatment. It is necessary for the technologist to know some basic anatomy of the airway and identify its important features on a radiograph.

Fascial planes described in the neck

Three fascial planes are described in the neck: investing, pretracheal, and prevertebral fascia. The investing fascia is a layer that encircles the structures of the neck. It is firmly attached to the mastoid processes, zygomatic arches, mandible, hyoid bone, and spinous processes, manubrium, clavicles, and both scapula. It is important because it contains the jugular venous arch and some muscles of the neck.

Along the anterior portion of the neck is a thin layer of cervical fascia called the pretracheal fascia. It extends from the thyroid cartilage (C4) into the thorax. It is a split fascia which encloses the thyroid gland, trachea, and esophagus. Trauma to the trachea that results in a rupture of the trachea, or of a bronchus in the thorax can result in air seepage into the pretracheal fascial space. An acute swollen neck caused by air in the pretracheal fascia (mediastinal emphysema) may spread into the face along this route.

The prevertebral fascia covers the muscles of the vertebral column, extending from the base of the skull to about the third thoracic vertebra. Its importance to us is that it is firmly attached to the anterior longitudinal ligament which can contribute to its injury from trauma. Because the pharynx is surrounded by a buccopharyngeal fascia there is a space created between it and the prevertebral fascia called the retropharyngeal space. This space contains the great vessels from the aortic arch, the heart, the trachea, the thymus and part of the esophagus. This space is important because it allows for movements of these structures, such as the esophagus during swallowing, and the beating of the heart. Trauma causing perforation into this space is radiographically significant; therefore, the radiographer must have an understanding of the dynamics of this anatomy so that it is included on routine plain films.

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The picture above demonstrates the relative locations of the fascia, particularly noted is the retropharyngeal space, which is a potential space. Blood or pus that infiltrates into this space can spread to the superior mediastinum.

The airway

The airway begins just posterior to the nasal and oral cavities with the pharynx. The pharynx is the upper respiratory tract, but is common to both the digestive and respiratory systems. It conducts food to the stomach via the esophagus, and air to the lungs via the trachea. The airway can be seen in the picture above. Visualization of the airway is important to imaging of the traumatic cervical spine.


Vertebral and carotid arteries

There are four main arteries that pass through the neck in route to the brain to supply it with blood. These vessels are: the right and left vertebral arteries, and the right and left carotid arteries. An understanding of the gross anatomy of these vessels is important to radiographers because in certain types of trauma they could be injured. The goal of this brief review is to make the radiographer keener to the need of the patient toward other diagnostic test or surgery. It is not intended that the radiographer make a decision on patient care; however, valuable time should not be lost trying to get a good plain film radiograph when a CT scan may be quicker and more informative. An example would be to rule out a cervical spine injury from a fall, secondary to a gunshot injury. Now let’s consider the anatomy of these vessels.

The carotids and vertebral arteries in the neck have their origins from the great vessels arising from the aortic arch in the superior mediastinum.

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The picture above is a 3D reconstruction from axial CT data (bottom left), and drawing demonstrating the origin of the vessels in the neck from the aortic arch. The radiograph shows the relative location of the origin of the great vessels in the superior mediastinum.

The blood supply to the brain from the neck is very important to survival because there are only four vessels that supply the entire brain with oxygenated nutrient rich blood. These vessels are the right and left vertebral arteries, and the right and left internal carotid arteries. Within the transverse foramina coarsens the right and left vertebral arteries in route to the brain supplying it with oxygenated blood. Each vertebral artery originates from its respective subclavian artery in the root of the neck (picture above). The vertebral arteries enter the transverse foramen of C-6 to ascend upward through the transverse foramina of C6-C1 entering the skull through the foramen magnum Through anastomoses these four vessels form contributories to the Circle of Willis supplying the brain with oxygenated blood. Any disruption in this supply can have grave consequences to the individual. Traumatic injury to these vessels can be evaluated by angiography, or in some cases with intravenous contrast CT angiography.

The bony spine protects the vertebral arteries; but only muscles and soft tissues of the neck protect the carotid arteries as the picture below shows. Injury to blood vessels like the carotids and vertebral arteries must be considered in certain types of traumatic injury to the neck or chest.

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The picture above is of a 3D volume rendering of the carotids and vertebral arteries reconstructed from axial CT data (above). Notice that the patient is intubated.

There are many smaller branches of these vessels in the neck that can be injured in certain types of trauma. The picture below demonstrates the extensive gross anatomy of the arterial supply to the neck from the great vessels in the thorax.

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The two pictures above of MR angiograms of the neck vessels demonstrate the extensive pattern of arteries in the neck that supply the brain.

Cervical spinal nerves

One of the most important understandings the technologist must gain is an appreciation for the fact that injury to a vertebra does not necessarily mean that there is an injury to the spinal cord; neither does injury to the spinal cord require a vertebral fracture for correlation. Neurological examination of the patient and radiographic interpretation by a radiologist is what determines what further testing is needed before a definitive diagnosis can be given. In many case instances the radiologist in consultation with a neurosurgeon may recommend a CT scan, and possibly magnetic resonance imaging, or even fluoroscopy guided spine motion studies. The point here is that the radiographer should be aware that injuries to spinal nerves or to “soft” tissue are issues in trauma care as well as awareness of bony injury. Traumatic injuries to the spinal cord or the spinal nerves may occur during a trauma event.

A basic understanding of the gross anatomy of spinal nerves as part of ones understanding of the scope of trauma imaging and patient care is in order. In addition to the anatomy of the spinal nerves, the technologist should be aware that some sensory nerves carry more than just pain or the absence of pain; there is also touch, pressure distinction, two-point discrimination, temperature, proprioreception, and other sensory and motor functions. The complete picture of the patient is gathered by the physician performing the clinical evaluation, augmented with diagnostic testing. A brief review of the gross anatomy of the spinal nerves that exit the spinal cord is beneficial to ones imaging skills. It is difficult to know when an image is sufficient for diagnosis unless one knows what the elements of the diagnosis entail. Certainly a complete survey of the bony relationship to the spinal nerves and vertebral canal are necessary. Therefore, we should review the gross anatomy of the spinal nerves.

The gross anatomy of the spinal nerves is that there are thirty-one pairs of spinal nerves having attachments to the spinal cord. These are arbitrarily divided into 8 pair of cervical spinal nerves, 12 pair of thoracic nerves, 5 pair of lumbar nerves, 5 pairs of sacral nerves, and one coccygeal nerve. The eight pair of cervical nerves exit the spine in the following way: the first cervical nerve exits above the first cervical vertebra between it and the skull, the second cervical nerve exits below the first cervical vertebra between C1 and C2, the third cervical nerve below the second cervical vertebra, the fourth cervical nerve from below the third cervical vertebra between C2 and C3, the fifth cervical nerve from below the fourth cervical vertebra, the sixth cervical nerve from below the fifth cervical vertebra, the seventh cervical nerve from below the sixth cervical vertebra, and the eighth cervical nerve from below the seventh cervical vertebra between it and the first thoracic vertebra. Therefore, to effectively demonstrate potential injury to the eighth cervical spinal nerve the radiographer must demonstrate the vertebral body, apophyseal joints, and quadrilateral posterior architecture of both C7 and T1 vertebrae. The alignment of the 7th cervical and 1st thoracic vertebrae must also be demonstrated.

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The drawing above demonstrates the pattern for the exit of the eight pairs of cervical spinal nerves from the vertebral canal. These are mixed nerves carrying sensory and motor distributions.

The spinal nerves exit the vertebral column through the intervertebral foramina. Each intervertebral foramen is formed by the pedicles of adjacent vertebrae, which have notches on their superior and inferior borders. The inferior vertebral notch and superior vertebral notch of adjacent vertebrae form the intervertebral foramen (arrows-picture below). Within each foramen lies a dorsal root ganglion of a spinal nerve.

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The radiographs above are oblique views of the cervical spine. The left picture is a RPO view, and the radiograph on the right is a LPO position. Notice the arrows in the right picture pointing to the superior and inferior vertebral notches on adjacent vertebrae. The pedicles form the intervertebral foramina; however, the atlas does not have pedicles nor does it form any intervertebral foramina.




Section 1.4 Plain Film Radiographic Imaging of the Traumatic C-spine

Trauma imaging of the cervical spine begins with a high suspicion for vertebral or spinal cord injury. Standard radiographic views are obtained with the patient supine, fully supported on a spine board, with neck collar and immobilization apparatus in place. The standard trauma film series at most institutions are: a horizontal beam lateral and Swimmer's view (if necessary), anterior-posterior (AP) view, and open mouth odontoid view.

Diagnostic imaging technologists should be aware of the indications for special views of the cervical spine such as: inability to adequately visualize all vertebrae (especially C2 and C7/T1), questionable fracture of articular pillar, a question of a fracture in the axial plane, a question of possible fracture fragments near the cord. Additional views if needed are the: Swimmer’s, Fuchs, and panorex views; and/or CT, and MRI.

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The minimum standard radiographic images taken to evaluate the cervical spine following acute trauma are: a horizontal beam lateral, an AP view, and the open mouth odontoid view. When injuries are serious enough or these views do not adequately demonstrate all diagnostic criteria, the physician may request a CT and/or MRI studies of the cervical spine.

Besides knowing what the standard protocol is for trauma imaging of the cervical spine, assuring that the diagnostic criteria is met for each view taken is the overriding principle. This is important because the radiographer is usually the first to see the radiographic images and must make a decision on whether to submit the images for physician interpretation, or to repeat the imaging sequence until images with the diagnostic criteria is accomplished. Therefore, the advanced imaging specialist must know the diagnostic criteria for each view and assure that it is met in a timely manner. Also, the technologist must know when enough radiographs have been attempted and a consultation with the radiologist is appropriate since other imaging modalities may be needed to acquire sufficient diagnostic information. You should be aware that the radiographer is legally responsible for image quality and the radiologist for the acceptance of all radiographic images they interpret. Therefore, the radiographer must assure that they have met the diagnostic criterion for each view. Before the radiographer submits an image for diagnosis there are at least three things that must be well thought-out. The first is that the patient is properly positioned. Secondly, that the path of the central ray is correct. Third, has the diagnostic criteria for the view been met?


Trauma crosstable lateral c-spine view

The lateral cervical spine view of a trauma patient is always made while the patient is lying supine on a spine board, or on a rigid transfer board. The x-ray beam is horizontal to the long axis of the patient. With the patient in this position, and the beam projected horizontally the radiographic view is called a horizontal beam lateral (a.k.a: crosstable lateral or X-table lateral view). This is the standard for trauma imaging of the cervical spine whether the physician specifies the view or not.

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The picture above of two technologists working to assure an adequate horizontal beam lateral of the cervical spine is made.

The mid-sagittal plane may be aligned by manipulating the spine board, but never move the patient. Under no circumstance should the radiographer pull down on the shoulders of a patient in order to image more vertebrae. For trauma imaging all such practices of forcing the patient’s body into a particular position are contraindicated. Time should also be taken to make sure monitoring leads do not interfere with the diagnosis by obscuring anatomy. If the table or bed is adjustable, adjust them to a comfortable vertical working height. This will minimize the potential for back strain while working with the patient.

Excessively poor alignment of the patient such as when the neck is bowed because the spine collar is too large may cause the image to be distorted. The "as is image" is acceptable during trauma imaging although alignment of the patient should be attempted, but only by moving the support board rather than the patient. Either sufficient diagnostic radiographs are made in the “as is” position, or the radiologist should be consulted to recommend other imaging procedures. The radiologist may recommend a CT or MRI if it will increase the diagnostic sensitivity.

The technologist should observe whether there is discharge from either external auditory meatus. Including the sphenoid sinus on the crosstable lateral would be indicated for a trauma patient who presents with bleeding from the ear, or who has cerebral spinal fluid discharge from the external auditory meatus. An air-fluid level in the sphenoid sinus could indicate a fracture of the base of the skull.

Soft tissue injury is very important to trauma imaging of the spine, especially in the case of penetrating injuries like gunshot injury, stabbing, whiplash, and so forth. Soft tissue structures should be adequately demonstrated in all views. In fact, all four fundamental subject densities should be demonstrated adequately on all radiographic images. From radiopaqueness to radiolucency these densities are: bone, muscle, fat, and air; together they make up subject detail and contrast.

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The radiograph above is a horizontal beam (crosstable) lateral view of the cervical spine. Without exception, this is the standard trauma view of the cervical spine.

Now what constitutes an acceptable lateral radiograph of the cervical spine? The radiographer should make sure that the field of view (FOV) includes from the base of the skull through the first thoracic vertebra. There should be minimal rotation and misalignment of the vertebrae. In addition, the radiographic technique should provide enough bony detail so that the three contour lines can be easily drawn. Soft tissue structures within the anterior and posterior margins of the skin should be included and not “burned out” on the film. Alignment of the three contour lines must be easily made from the film silhouette. The entire anterior and posterior architecture of the vertebrae must be must be visualized. Consider the radiograph below!

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The radiograph of a horizontal beam lateral (above) has the three contour lines drawn. The anatomy delimited by the boundaries of these lines is not clearly seen through the first thoracic vertebra. Therefore, the diagnostic criterion that C1-T1 must be demonstrated on the crosstable lateral view is not completely met.

The radiograph above does not adequately demonstrate the posterior architecture of the first thoracic vertebra. This must be corrected by either repeating the image using more exposure technique, or adding a horizontal beam Swimmer’s view to the study.

Now before we leave the topic of the crosstable lateral C-spine it must again be emphasized that under no circumstance should the shoulders be pulled down to evaluate the traumatic cervical spine. Now if the saying is true that one picture is worth a thousand words, then the three pictures below are worth a million words all repeating the messages never pull down on the shoulders of a trauma patient to image the cervical spine. There are other options if the lateral view inadequately demonstrates all of the vertebrae.

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The picture above is a crosstable lateral radiograph of the cervical spine of an unconscious trauma patient. The atlas and axis are disjoined. The image demonstrates why pulling the shoulders is contraindicated.
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The horizontal beam lateral radiograph above demonstrates misalignment of the vertebrae (subluxation) at C5/C6. Notice that vertebrae C6 through T1 are not adequately visualized.
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If the technologist had pulled down on the patient’s shoulders to image this person’s spine, paralysis may have occurred.

Horizontal beam lateral Swimmer’s view

The Swimmer’s view is part of the routine imaging of the traumatic cervical spine whenever the distal cervical spine is not adequately visualized. If the patient’s condition permits then the arm is raised on the side closest to the image receptor. The opposite shoulder is depressed so that the CR passes through the level of the coricoid process. If the patient has upper extremity injuries, then the opposite arm is raised and the shoulder closest to the film is depressed (reverse Swimmer’s).

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In the picture above the patient is positioned for a reverse Swimmer’s view. Either arm may be raised depending on the patient’s condition.

When imaging the lower cervical vertebra, such as C-6 to T-1, the longitudinal lines, posterior architecture, and apophyseal joints must be demonstrated. A coned down Swimmer's view gives better detail than does the full C-spine Swimmer's view, especially when using digital computerized imaging. This is because contrast and detail is improved greatly with the use of a cone because there is less scatter. Using a beam restrictor does not in itself create a problem in determining which vertebra is T-1. Some radiologists require the technologist to do a full cervical spine Swimmer’s view, others will accept the coned down swimmers so long as the three contour lines can be drawn through T1 and its posterior architecture is clearly visualized.

Collimation is also important to radiographic detail and is a part of the overall practice of ALARA (as low as reasonable achievable); however, when imaging the neck and soft tissue structures the entire pharyngeal shadow including the anterior skin line should be included. Care should be taken not to collimate anatomic structures of the neck out of the radiographic image during the trauma survey. As the radiographer views each radiographic image one must be keenly aware that each image is a diagnostic viewpoint for the radiologist.

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The two crosstable lateral Swimmer’s views above demonstrate the apophyseal joints formed by C7/T1, and the posterior architecture of C7. The three contour lines can be drawn through T2 on this radiograph which completes the diagnostic criteria for the lateral image(s) of the cervical spine.

When using a cone it is important to not only demonstrate C-7/T-1, but to assure that there is a complete overlap between the vertebrae seen on the crosstable lateral and Swimmer's view. For example, if the lateral view only demonstrates C1-C5, then the Swimmers must demonstrate from C-5 thru T1. This is often missed when for example the horizontal beam lateral only demonstrates the first three or four cervical vertebra. The Swimmer's view then must demonstrate C-4, C-5, C-6, C-7 and T-1 vertebrae, or a better lateral cervical spine view that includes more of the upper vertebrae is required.

The picture below is of a full cervical spine lateral Swimmer’s view. The three contour lines can be drawn for assessment of alignment; however, the detail of the posterior architecture and apophyseal joints of C7/T1 are more difficult to distinguish. Some radiologists require the full spine Swimmer’s view because the vertebrae are more easily counted. Unless there is accuracy in identifying the structures and number of the vertebrae, the coned Swimmer’s view may not be helpful. In such cases the radiologist must be consulted since a CT scan may be necessary to completely evaluate the spine.

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The two radiographs above are of the Swimmer’s view in which the entire cervical spine is imaged. The alignment of the vertebrae and the apophyseal joints can be assessed, and the vertebrae are easily counted for accuracy.

The AP cervical spine view

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The picture above (left) and radiograph (right) of an AP view of the cervical spine is another important routine view in the trauma imaging sequence.

The standard AP view is made with the patient on a spine support board and the mid-sagittal plane aligned. Moving the spine support board is the only option for aligning the mid-sagittal plane. Since the patient is immobilized and it is contraindicated to flex or extend the chin, the radiographer must angle the central ray to accommodate the patient's position. Special care should be taken to remove any metal objects such as monitor leads from the path of the primary beam. The cervical collar is not to be removed. The central ray is angled 15-20 degrees cephalic. This view should include all of the first thoracic vertebrae and as much of the proximal C-spine as is possible. Vertebrae one through three is difficult to image in the AP projection because of the mandible and base of the skull. Therefore, the open mouth odontoid view is recommended for completion of the AP series.


The opened mouth odontoid view

When the cervical collar is properly applied the upper incisors and base of the skull are at about a 15-20 degree angle from vertical when the mouth is opened. This requires the radiographer to angle the CR caudal so that it passes through the upper incisors and base of the skull. This angle varies depending on the anatomical skull type and may occasionally exceed 25 degrees caudal angulation. This view is possible only when the patient is alert and cooperative; however, with the unconscious intubated patient this view should be omitted and a CT scan performed.

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The picture above (left) shows the patient and tube alignment for the open mouthed odontoid view. The radiograph (right) shows the image of C1 and C2. The atlantooccipital joints and the atlantoaxial joints are well visualized.

The diagnostic criteria for the open mouth odontoid view include three basic alignments: 1) the alignment of the lateral margins of C1/C2 vertebrae, 2) spacing of the two atlantoaxial joints, and 3) the appearance of the spacing on either side of the dens. The three indices are indicated by lines in the picture below.

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During trauma imaging the technologist should strive to demonstrate the odontoid with even spacing on either side of the odontoid peg. The space formed by the atlantoaxial joints should be even and the lateral margins of the joint should be aligned without moving the patient to accomplish the image.

The Fuchs view of the odontoid tip

Occasionally, the tip of the odontoid process is not adequately visualized and the technologist may include what is known as a Fuchs view. The Fuchs view of the dens is not reliable for diagnosis unless it is specifically used to visualize only the superior third of the odontoid tip.

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The Fuchs view (left) is considered unreliable for trauma imaging of the cervical spine unless it is used to demonstrate the upper third of the odontoid tip. The amount of distortion due to extreme angulation of the CR makes this view questionable for diagnostic purposes. A 3D reconstruction from axial CT data (right) shows the odontoid tip projected through the foramen magnum mimicking the Fuchs view. The distortion of the tip and associated joints is plainly seen. Therefore, a complete CT scan is preferred over additional plain film images if the odontoid is not adequately visualized.

The Fuchs view is a type of modified Water’s view to demonstrate the odontoid tip. If the patient has not suffered trauma and can extend the chin upward so that the tube is not angled, the view may have greater significance. But with the acute angle required to see the odontoid tip when the patient is in a cervical collar and the neck cannot be extended makes the view quite unreliable.

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The radiograph above of the full skull demonstrates that the odontoid process can be demonstrated by an exaggerated reverse Waters view called the Fuchs. When performed correctly is very useful for demonstrating the upper part of the odontoid tip but is not used for trauma imaging.

The orthopantomogram of the cervical spine

Another practice for imaging the odontoid is the orthopanorex view (a.k.a. Panorex). This is a type of tomography that can be useful for imaging but is not recommended for trauma. But because some institutions still use supine panorex imaging of trauma patients it is covered here.

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The picture above (left) shows an orthopanorex machine that is used primarily for imaging the mandible. A major reason why many trauma centers have the supine version of this imaging equipment rather than the upright orthopantomogram machine commonly used in dental offices is that it can be used for trauma patients. The image to the right is shows a panorex view of the cervical spine taken of a patient for which C1/C2 was obscured on the open mouth odontoid view. After multiple attempts to image the patient it was decided to try a panorex view. This is an equivalent alternative to a linear tomogram of the spine. Although this is not a common use of the orthopantomogram machine it demonstrates the flexibility of radiographic equipment and creative technical skills required for trauma imaging. Linear tomography and pantomogram imaging are almost completely replaced by CT imaging.



Section 1.5 Trauma Protocols ACEP/ACR

Now that we have discussed the plain film radiography of the Traumatic cervical spine, let’s consider some of the protocols that have emerged through recommendations by the American College of Radiology (ACR) and American College of Emergency Physicians (ACEP) for assessment of the cervical spine following trauma.

Radiographic Assessment of Cervical Spine Trauma

The initial assessment of spinal trauma radiography can be divided into three distinct cervical spine clearance surveys:

  • The unconscious intubated patient
  • The conscious symptomatic patient
  • Clinical clearance of the spine
  • The following trauma imaging recommendations are due in part to data from various studies that have documented a missed injury rate upwards to 33%. These failures are accounted for by failure to suspect injury, inadequate radiographic imaging, and a sequaelae that includes incorrect radiographic interpretation and clinical examination. The goal of these three distinct cervical spine clearance surveys is to implement radiological evaluation of the cervical spine consistent with high sensitivity standards for diagnosis. The different protocols address when other diagnostic modalities like CT, MRI, or fluoroscopy should be implemented. While the cervical spine remains the primary focus of trauma injury it should not be allowed to obscure thoracolumbar concerns, as 5% of spinal injuries have non-adjacent vertebral fractures.

    Unconscious intubated trauma patient

    The incidence of unstable spinal injury in the unconscious intubated patient, with potential spine injury, is about 10%, and therefore requires great concern and care.

    Recommended C-spine radiography of the unconscious intubated trauma patient:

  • Lateral cervical spine (occiput to T-1)
  • AP cervical spine (C-2 through T-1)
  • CT scan (occiput to C-3), or
  • CT of entire cervical spine may be requested

  • This protocol emerged from four significant observations: 1) clinical evaluation is incomplete in the unconscious patient. 2) The open mouth odontoid view is unreliable in unconscious intubated patients missing nearly 16% of injuries. 3) Ligamentous instability cannot be completely excluded with plain films. 4) Up to 15% of cervical spine injuries are missed when the lateral view alone is used to clear patients. What this protocol means to the general diagnostic radiographer is that valuable time should not be wasted trying multiple attempts to demonstrate portions of the c-spine. The accepted protocol involves the CT scan early in the imaging process for the intubated patient.

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    The two radiographs above of an intubated patient: the crosstable lateral view (left) can be accomplished with minimal obstruction of the view; however, the odontoid view shown is considered unreliable for diagnosis. Many institutions still attempt the open mouth odontoid view of intubated patients, but it is recommended that a CT scan of the cervical spine be made in this trauma scenario.

    Cervical spine CT protocol


    Axial thin cut CT scan in bone window with coronal and sagittal 2-D reconstruction of the upper cervical vertebrae, along with plane film radiography has a reported false negative rate of less than 0.1%. For the diagnostic and CT radiographer this means that high specificity and sensitivity is achieved through combined imaging protocols, rather than a single protocol, when the patient first undergoes plain film imaging.

    Another emerging option in trauma radiography is imaging the entire cervical spine with CT. Generally this is done when the patient suffers multiple trauma injuries to the head, chest, abdomen, pelvis, cervical spine, thoracic spine, and lumbar spine. The procedure requires thin-cut slices from the occiput through the first thoracic vertebra. The data is augmented into coronal and sagittal reconstructions. What is quite interesting about full cervical spine CT data is that to date no study has missed an injury that was seen on plain film. With multiple trauma injuries this may become the study of choice in dealing with the unconscious intubated patient.

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    The three radiographs above are axial CT thin slice cuts through C2 on a patient that is intubated. The open mouth odontoid view did not demonstrate the extensive fracture through the body of the vertebra. This is why the open mouth odontoid view is considered unreliable for the intubated patient. Notice the endotracheal tube in the radiographs (arrows).

    In addition to axial CT imaging, sagittal and coronal images of the cervical spine can be made. The three sagittal images (below) demonstrate how whole cervical spine CT imaging is making its way into the mainstream of trauma imaging. In some cases it is clear that CT should be the first choice in imaging the spine. When multiple radiographic CT studies of a trauma patient are required, it is quicker and better to get a CT scan of the spine in these critically injured patients. In terms of CT imaging of the cervical spine following a questionable plain film radiographic study, CT imaging has a reported accuracy of about 99.4% and greater for whole cervical spine imaging. Computerized tomography images can be reconstructed in various 2-D anatomical planes and even into 3D data images if requested. Notice the fracture of the axis (C-2) in the three CT images below, these CT images provides better information than plain film radiographs alone.

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    The above three pictures demonstrate how CT axial images can be reconstructed into sagittal images for evaluation of the traumatic cervical spine. Some institutions have implemented a trauma c-spine series that includes down to the fourth thoracic vertebra thereby providing a good look at the first three thoracic vertebrae from a sagittal view. The lateral view of the lower cervical and upper thoracic vertebrae is difficult to image with conventional plain film.

    Conscious symptomatic patient


    Recommended C-spine radiography of the conscious symptomatic trauma patient:

  • Lateral cervical spine (occiput to T-1)
  • AP cervical spine (C-2 through T-1)
  • Coned Swimmers view if necessary
  • Open-mouth odontoid view
  • CT scan of inadequately demonstrated vertebrae
  • It should be attainable for the radiographer to accomplish a high quality lateral, AP and odontoid view of a conscious patient. Their cooperation can be called upon to achieve additional views like the Swimmer’s or Fuchs views if necessary. The conscious patient's condition may change and unconsciousness may ensue depending on the extent of injuries. Nursing and respiratory therapy members of the trauma team generally monitor patients with multiple trauma injuries who are able to leave the emergency department suite for diagnostic testing.


    Clinical clearance of the cervical spine

    Clinical clearance of the cervical spine without radiographs:

  • Generally does not involve diagnostic radiographic images; however, if requested:
  • Upright lateral (and possible flexion/extension views)
  • an upright or supine AP and odontoid views,
  • Only on request are both 45 degree oblique views done.
  • Clinical clearance has nothing to do with radiology because these patients generally do not present to the radiology department for radiographs. Only the examining physician can clear these patients. But what is important here is that the radiographer does not assume that a patient should have been or could have been cleared clinically. The typical scenario here is that a patient presents himself or herself at the emergency room several days following a MVA. These patients are usually fitted with a soft cervical support collar and walked over to the diagnostic imaging department for radiographs. A common assumption among radiographers is that the examination maybe unnecessary. However, be aware that these patients are not in the category of clinically clearance and that is why the physician makes a request for radiographs. There are reported cases of ambulatory patients who fit this scenario and upon radiographic imaging spinal injury was found. Therefore, the radiographer should maintain a high suspicion for injury concerning all post traumatic spine requests, ambulatory or not. The following chart lists the standard views of the traumatic cervical spine that may be requested on ambulatory patients:


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    The table above lists the common views of the cervical spine that may be requested for ambulatory patients. An ambulatory patient for whom a physician request images of the cervical spine are not clinically cleared, therefore, the images. Oblique views or flexion and extension views may also be requested.

    Additional studies of the cervical spine

    In some cases where unstable fractures are found, a definitive diagnosis as to the full extent of injuries and prognosis requires additional studies such as magnetic resonance imaging (MRI) or dynamic flexion-extension fluoroscopy. The unconscious patient requiring additional radiological evaluation, such as MRI, may be sent to the intensive care unit with full spine precautions to allow time to see if consciousness is regained to the benefit of further assessment. Often these patients are observed for 24-48 hours or until consciousness is regained then a complete neurological assessment can be made. At some point the patient may be transported to the magnetic resonance imaging suite since MRI is more sensitive for soft tissue injury than CT or plain film radiography. Currently, MRI is not the choice examination for the initial trauma evaluation workup mainly because all equipment used to support the unconscious intubated patient would have to be non-ferromagnetic. Metallic flight risk to the patient and coworkers would be greatly increased as non ferromagnetic support instruments are not widely in use.

    Another examination that has gained some popular use is dynamic flexion-extension of the cervical spine using a C-arm. Stressing of the spine by flexion and extension is passive and should only be performed by an experienced clinical physician. Literature shows that fluoroscopic examination of the unconscious patients has a specificity of about 99% and a sensitivity of 92%. Of the 625 patients reported to have undergone dynamic fluoroscopic examination, two suffered neurological deterioration, one of which suffered complete quadriplegia from the procedure. The use of dynamic flexion-extension C-spine imaging is currently undergoing research scrutiny.

    Angiography may be required to further evaluate potential injuries to blood vessels. In the case below, the patient was quickly evaluated and found to have a gunshot injury that required angiographic evaluation. The patient was an innocent bystander who was waiting at a bus stop and suddenly felt a stinging burning sensation in his neck. He and witnesses did not hear gunshot fire which occurred a good distance away. Efficiency in dealing with this patient in the conscious state diverted what could have been a life threatening situation. Understanding that imaging is not the end point for the patient should help the radiographer perform quality studies efficiently. In addition, having digital imaging and PACS allowed these images to be viewed by many participant physicians who monitored the results of diagnostic x-rays, CT, and interventional imaging of the patient (see picture below).

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    The radiograph above is of an angiograph of a patient who suffered a gunshot injury. The bullet was discovered during plain film imaging of the cervical spine of an acute conscious trauma patient. The point here is that the radiographer must always remain aware that the patient may have other injuries besides vertebral fractures. The neck was evaluated in the interventional radiology department as part of an angiography study.

    Trauma imaging requires the technologist to be aware of the patient's history and make adjustment to the sequencing of diagnostic images. For example, a gunshot injury or stabbing may place chest imaging above neck and spine imaging. But as a rule, MVAs, diving injuries, etc. will have a high priority for spine imaging first. Critical trauma such as gunshot injury or motor vehicle accidents require that the technologist be able to quickly complete imaging while the patient is monitored by the trauma team.

    It is worthy of mention that an institution that have digital imaging and picture archiving and communication system can handle critical trauma better than those that do not. Because PACS images are made available to the radiologist, surgeon, and the emergency room physician simultaneously, treatment and further diagnostic testing can be made expediently. Because of computerized digital imaging and PACS, in the case of the gunshot wound to the neck evidenced by a lateral spine view, the angiography team was informed to prepare for the patient “stat.” When it comes to trauma radiography, all radiology modalities can be integrated into PACS, which is rapidly becoming the hallmark of trauma radiography.

    Some medical centers still use oblique cervical spine views in their trauma protocol. Literature shows that adding oblique views to the trauma protocol does not increase the sensitivity of radiographic evaluation; however, there is better information about the posterior spine structure than is presented with the standard AP cervical spine view. Computerized tomography has completely replaced the need for trauma oblique views.


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    Common injuries of the cervical spine

    • Penetrating injury such as a gunshot wound that may have traversed the spine.
    • Hangman's Fracture - caused by simultaneous extension and distraction as in being “clothes lined” at high speed, or during a MVA in which the head is forced against the car roof creating compression followed by an extension vector.
    • Odontoid Fractures - are classified as type I, type II, or type III fracture:
      1. Type I odontoid fractures involve only the tip of the dens and are mostly considered stable.
      2. Type II fractures are the most common type involving the dens and body of C-2 vertebra. Following reduction the patient placed in a halo and/or surgical fusion may be necessary.
      3. Type III odontoid fractures have deep nonunion into the body of C2 vertebra.
    • Jefferson Fracture - is a type of burst fracture of C-1 vertebra. It can occur from an acutely severe axial force causing compression. If the force is great as in diving injuries, the vertebral arch or body of adjacent vertebra literally burst. In the absence of bone fragments penetrating the spine survival without neurological deficit occurs in about 50% of patients, especially if the lateral masses are forced laterally away from the spinal cord.
    • Rotational Injury - Involves complex forces caused by injury onto the head or neck. When rotational injuries involve hyperextension, complex fractures to the interarticularis and pedicle(s) may occur. A "jumped facet(s) phenomenon man occur either unilateral or bilaterally. In some cases the subluxation may be unstable such as when the facets are jumped but not locked.
    • Extension teardrop fracture – Caused by an avulsion of the anterior part of a vertebral body during hyperextension.
    • Clay-shoveler’s fracture – A fracture of the spinous process of C6, C7, or T1. It is due to hyperflexion injury and may involve one or more spinous process.
    • Unilateral locked facet – caused by flexion and rotation injury. The intervertebral foramina is visible above but no below on the true lateral view.
    • Bilateral locked facets – also caused by hyperflexion injury. The upper cervical spine is anteriorly displaced over the lower spine. A clue to this injury is widening of the spinous processes at the site of injury. This results in a complete luxation (dislocation) of the spine.
    • Muscle spasm: loss of normal lordotic curve (lateral view), or torticollis on AP view.

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    Section 1.6 Case Study: Multi-Radiography approach

    The following is a case study of a young male involved in a motor vehicle accident. He arrived at a trauma center as a Trauma Team Alert (TTA). Upon stabilization the patient was transported by the TTA team to diagnostic radiology for among other x-rays, a trauma cervical spine series. The following radiographic views were obtained: crosstable lateral, horizontal beam Swimmer’s view, AP, open mouth odontoid views. The purpose of this case study is to further the awareness of radiographers from the different modalities to the contributions of their colleagues towards trauma imaging of the cervical spine.

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    The two radiographs above: a horizontal beam lateral (left) and a horizontal beam Swimmer’s view (right) were taken immediately upon arrival in the radiology department. There was suspicion for injury at C7 based on these films. The completed study included the AP view and two attempted open mouth odontoid views (below).
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    Consider the three radiographs above: the AP view (left) and odontoid views (middle and right) completed the plain film images of the patient’s cervical spine. Notice that the AP view adequately meets the diagnostic standards for plain film imaging. Vertebrae C2 through T2 are adequately imaged and show a possible fracture in the region of the seventh cervical vertebra. The two odontoid views do not fully meet the diagnostic criteria, therefore, a CT scan of the entire spine was ordered upon consultation with the radiologist. This is an adequate study by the general radiographer when additional studies (CT or MRI) are not made. But because a CT scan was performed the study is adequate for the patient’s condition.

    CT evaluation of the cervical spine following routine plain films

    The CT evaluation included axial thin slices from the occiput through the 3rd thoracic vertebra, and 2D reconstruction in sagittal and coronal planes.

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    The pictures above are axial CT thin slices through the 7th cervical vertebra. It demonstrates a fracture with fragmentation in the body of the vertebra. This study was performed upon recommendation of the radiologist who viewed the plain films of this trauma patient. These pictures further emphasize the need for quality images of the entire cervical spine especially the atlas/axis junction, and the C7/T1 junction.
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    These 2D sagittal reconstructed images of the cervical spine are part of the routine imaging sequence for CT imaging of the cervical spine. In terms of our case study it demonstrates why CT is an added value to imaging the spine being that the fracture at C7 is well described.
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    The pictures above are 2D coronal CT images of the cervical spine. They demonstrate well the contribution of CT imaging to the cervical spine. Again, the fracture of C7 is well visualized and described in many planes of the coronal slices.

    Because there is a fracture of the seventh vertebra that involves the vertebral foramen, a MRI scan was requested to determine if the injury involved the spinal cord. This patient did not have extensive neurological deficits on clinical evaluation.

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    This MRI study shows sagittal images of the cervical spine of our trauma case. The fracture and intrusion into the vertebral canal is well seen in these images.
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    The MRI radiographs above of axial images (1-6) and sagittal images (7-12) are T2 weighted. They demonstrate the contributions of MR imaging cervical spine trauma diagnosis. The area of the fracture is shown to evaluate for spinal cord injury. MR imaging is not the gold standard for trauma c-spine imaging because most trauma support materials are still not nonferromagnetic.

    Disability associated with spinal cord injury

    Disability associated with spinal cord injury (SCI) greatly depends on the severity of the injury and where in the spinal cord it occurs. Acute care and rehabilitation goals are to minimize long-term disability. Most people with a SCI regain some function within a few days to six weeks following injury; however, beyond six weeks the prognosis diminishes greatly. Corticosteroids, cord decompression, and surgical stabilization of the vertebrae are all acute treatment strategies aimed at reducing further injury. A complete spinal cord injury produces total loss of all motor and sensory function below the site of injury. A spinal concussion may produce complete or incomplete cord dysfunction that resolves in a day or two. When nerve cells and pathways in the center of the spinal cord are injured such as in central cord syndrome, there is weakness and possibly paralysis of the arms with some degree of sensory loss.

    Central cord damage generally spares the lower extremity. Anterior cord syndrome occurs from injury to the anterior parts of the spinal cord's motor and sensory tracts. These patients have crude sensations but motor and relative sensations are lost. Posterior nerve pathways that are intact do carry some sensations but motor skills are lost. Brown-Sequard Syndrome results from injury to either the right or left half of the spinal cord. Motor and some sensory sensations are lost below the level of injury; pain and temperature sensation is lost on the opposite side of injury. Many other types of nerve damage are seen according to the distribution pattern of the nerve(s) injured. Another post-traumatic consequence of spinal cord injury is syringomyelia which affects about 2% of spinal cord patients. It is caused by cavitations in the central segments of the spinal cord producing pain, muscle weakness, and sensory loss. The cavitation tends to ascend up the cord especially in the cervical spine region and may require draining to relieve the pain associated with the cavity.

    Untimely spinal cord injury produces a chronology of denial and anger over the permanence of the disability. Depression and lowed self-esteem is a common pattern in the disabled patient. The technologist should be aware of emotional difficulty these patients suffer as many follow up radiographs may be required. Paraplegics will have to be trained to use the muscles of the upper arms in order to affect motility via wheelchair. Tetraplegics will be restricted to a special adopted electric wheelchair through which they too can achieve restricted motility.




    Summary Points to Ponder!

    • Spinal cord injury is an injury to the spinal cord or nerve tracts that relay signals to and from the brain and body.
    • Traumatic spine injury occurs in approximately 1 in 10,000 individuals per year, mostly males in their teens or twenties.
    • Management of the potential spine injury includes immobilization in the neutral position, cervical collar, side head supports, and perhaps strapping of the shoulders and pelvis so that the spine is not the center of rotation.
    • Logrolling a patient requires one person to stabilize the head and two persons minimum on each side of the patient to keep the spine aligned.
    • The basic parts of a vertebra are: body which is anterior and an arch posteriorly which consists of the pedicles and laminae.
    • Seven appendages arise from the arch: two transverse processes laterally, two superior articular processes, two inferior articular processes, and one spinous process.
    • The distinguishing feature of the cervical vertebrae is the presence of transverse foramen in the transverse process. Within them coarsens the vertebral arteries.
    • Four vessels supply the entire brain with blood: two vertebral arteries that coarsen in the transverse foramen of cervical vertebra, and the two internal carotid arteries in the neck, together they give tributaries to the Circle of Willis.
    • Arterial damage to the vessels of the neck can be quickly visualized with CT angiography and 3D reconstruction or magnetic resonance angiography (MRA).
    • Superior and inferior articular processes of adjacent vertebrae form apophyseal joints of the spine. These are diarthroses, which are synovial joints having unlimited motions.
    • The intervertebral disc is a symphyses type joint consisting of concentric outer fibrous rings called the annulus fibrosus and an inner nucleus pulposus which is a liquid moiety.
    • Atlantoaxial joints are formed between the atlas and the occipital condyles, two atlantoaxial joints are formed between the atlas and the axis.
    • The atlas does not have pedicles, laminae, or a spinous process. Instead it has two lateral masses that contain superior and inferior articular processes, and an anterior and a posterior arch. Transverse processes arise from the lateral margins of the atlas and have transverse foramen.
    • There are 8 pairs of cervical spinal nerves. These are mixed nerves having sensory and motor capabilities.
    • The site of exit for the spinal nerves that originate from the spinal cord is the intervertebral foramen formed by the inferior and superior vertebral notches on adjacent pedicles.
    • The standard trauma views of the cervical spine are the horizontal beam lateral, AP and AP odontoid views, and a Swimmer’s view if necessary.
    • Trauma c-spine images should be taken in the “as is” position and the spine not manipulated to align the patient. If possible the mid-sagittal plane should be aligned by moving the spine board.
    • Three lines are used to check for subluxation of the spine: Anterior contour line which runs along with the anterior longitudinal ligament, posterior contour line that runs the path of the posterior longitudinal ligament, and the laminospinal line. These should be demonstrated from the occiput through the first thoracic vertebra.
    • In addition to the contour lines the posterior quadrilateral architecture of the vertebra should be clearly visualized radiographically. This is especially true if the Swimmer’s view is added to evaluate potential injury to the 8th cervical spinal nerve.
    • Pulling down on the shoulders to get all of C7/T1 is contraindicated in acute trauma with suspected vertebral injury; instead a CT scan should be done if the plain films are inadequate.
    • When a lateral film alone, such as a portable lateral c-spine view, is used to clear the cervical spine, approximately 15% of vertebra injuries are missed.
    • Plain film radiographs followed by CT has a reported false negatives of 0.1%.
    • CT imaging of the entire cervical spine has a accuracy of about 99.4% and is preferred at many institutions for acute trauma screening.
    • The open-mouth odontoid view is considered unreliable for the intubated patient because it has a false negative rate of about 16%.
    • MRI while is a definitive study for cervical spine trauma is not preferred because of the metallic flight risk that high intensity trauma poses.
    • Fluoroscopic dynamic flexion and extension studies while having an 92% sensitivity and 99% specificity is not the safest procedure with reported paralysis of a patient in research trials.

    References

    • Bazzoli, G. 1999. Community based trauma systems development: key barrier and facilitating factors. Journal of Trauma, 47 (3):S22-33.
    • Committee on Trauma, American College of Surgeons. 17976. Optimal hospital resources for care of the seriously injured. Bulletin of the American college of Surgeons, 61:15-22.
    • Kirshenbaum, K.J., Nadimpalli, S.R., Fantus R., et al: Unsuspected upper cervical spine fractures associated with significant head trauma: Role of CT. Journal Emergency Medicine 8:183-98, 1990.
    • Scenarts PJ, Diaz J, Kaiser C., Prospective comparison of admission computed tomographic scan and plain films of the upper cervical spine in trauma patients with altered mental status. Journal Trauma. 2001 Oct; 51(4):663-8.
    • Brooks RA, Willett KM, Evaluation of the Oxford protocol for total spinal clearance in the unconscious trauma patient. J. Trauma 2001 May; 50(5):862-867).
    • Davis JW, Kaups KL, Cunningham MA: Routine evaluation of the cervical spine in head-injured patients with dynamic fluoroscopy: a reappraisal. J Trauma 2001 Jun: 50(6):1044-7.
    • Sees DW, Rodriguez Cruz LR, Flaherty SF. The use of bedside fluoroscopy to evaluate the cervical spine in obtunded trauma patients. J Trauma 45:768-71. 1998.
    • Barba CA, Taggert J, Morgan AS: A new cervical spine clearance protocol using computed tomography: J Trauma. 2001 Oct: 51(4): 652-6.
    • Berne JD, Velmahos GC, El-Twil Q; Value of complete cervical helical computed tomographic scanning in identifying cervical spine injury in the unevaluable blunt trauma patient with multiple injuries: a prospective study. J Trauma. 1999 Nov: 47(5): 896-902.
    • McNamara RM, Heine E, Esposito B: Cervical spine injury and radiography in alert, high-risk patients. J Emerg Med 8:177-82, 1990.
    • Mirvis SE, Diaconis JN, Chirico PA: Protocol-driven radiologic evaluation of suspected cervical spine injury: Efficacy study. Radiology 170: 831-4. 1989
    • West OC, Anabari MM, Pilgram TK et al, Acute cervical spine trauma: diagnostic performance of single-view versus three-view radiographic screening. Radiology 204: 819-23. 1997.
    • Woodring JH, Lee C: Limitations of cervical radiography in the evaluation of acute cervical trauma. J Trauma 34: 32-9. 1993.
    • MacDonald RL, Schwartz ML, Mirich D, et al: Diagnosis of cervical spine injury in motor vehicle crash victims: how many x-rays are enough? J Trauma 30: 392-7. 1990.
    • Special thanks to radiographers and physicians at Regions Hospital, St. Paul Minnesota, a Level I trauma center for their expert advice and radiographs.
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    Copyright image Copyright 2006 Nicholas Joseph Jr.






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