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Although computed tomography (CT) scanning of the cervical spine is commonly performed for neck injuries, plain film radiography is still carried out for patients who have sustained minor injuries with minimal neck pain, such as those who have suffered a fall.[1]
In older patients, imaging may reveal injuries to be more serious than is indicated by the nature of the trauma. In the case shown here (right), the elderly patient was neurologically intact but complained of upper cervical spine pain. Can you identify the cervical spine injury? Is it stable?
Image courtesy of Evan Oto | Science Source (Left) / Lennard A. Nadalo, MD (Right).
The cervical spine on this image demonstrates a normal curvature (yellow curved arrow) from the level of the C2 body down to C7, but the odontoid has been fractured and displaced posteriorly (white arrow).[2] This is an unstable injury that may be treated by long-term external stabilization, versus surgical internal fixation. The information from this lateral radiograph guided the acute management of the patient. The fracture was later confirmed by CT and magnetic resonance imaging (MRI) scans of the cervical spine.
Image courtesy of Lennard A. Nadalo, MD.
The nearly universal availability of CT scanning in emergency rooms makes reliance on cervical spine radiographs less critical. However, plain film radiography remains a first-line imaging modality used in the evaluation of patients with suspected cervical spine injury prior to transfer for cross-sectional imaging.[3-9]
The goal of cervical spine imaging is to determine the presence of an injury and to define its extent, particularly with respect to instability. Multiple views may be required to provide optimal visualization. The standard three views are the coned odontoid peg view, the anteroposterior (AP) view of the entire cervical spine, and the lateral view of the entire cervical spine. A "swimmer's" view can be obtained if the cervicothoracic junction is not clearly visualized on the initial exam.[10] Some radiologists prefer the routine addition of bilateral "trauma oblique" views to visualize the cervicothoracic junction in all patients and to evaluate alignment.
If there is any question of instability on the initial cervical spine radiographs or CT scans, passive flexion/extension views can be performed for further evaluation. Clinicians must be able to determine what makes a technically adequate radiograph, as well as recognize injuries. The lateral radiograph shown here demonstrates an unstable C5 teardrop fracture associated with cervical misalignment and prevertebral soft-tissue swelling.
Image courtesy of Lennard A. Nadalo, MD.
As seen on the diagram (left), the cervical spine can be divided into three columns: the anterior column, constituted by the anterior longitudinal ligament, anterior annulus, and anterior portion of the vertebral body (blue line); the middle column, constituted by the posterior longitudinal ligament, posterior annulus, and posterior portion of the vertebral body (broken black line); and the posterior column, constituted by all of the structures posterior to the posterior longitudinal ligament (red line).
As seen on the lateral cervical spine radiograph (right), the normal cervical spine consists of seven cervical vertebral bodies and supporting ligaments. The trachea (T) is anterior in position. Normally, the cervical spine has a slight anterior curvature (lordosis). The radiograph is from a 17-year-old female who was complaining of neck pain following a minor automobile accident. The cervical spine is straightened, which may be due to paravertebral muscle spasm, but it is otherwise normal.
Image courtesy of Lennard A. Nadalo, MD.
The lateral view of the cervical spine is the most valuable view in the evaluation of patients with cervical spine trauma. As seen on the image on the left, full visualization of the lower cervical spine and the cervicothoracic junction may be severely limited due to superimposed shoulder density, particularly in a larger patient. The increased frequency of obese patients has resulted in more "limited" cervical spine studies. In such situations, the use of a lateral swimmer's view allows better visualization of the lower cervical spine, as seen on the image on the right in this patient with a normal cervical spine. Even in an emergent situation, a lateral radiograph with full visualization of the cervical spine from the occiput down to T1 is mandatory. Limited cervical spine radiographic studies that do not demonstrate the T1 vertebral body must be supplemented by additional views or a CT scan of the cervical spine.
Image courtesy of Lennard A. Nadalo, MD.
The cross-table lateral radiographic view of this large patient (left) reveals the upper four vertebral bodies. The lower cervical spine (below the large, white arrow) and C1 (yellow arrow) are not adequately evaluated. In order for a lateral cervical spine radiograph to have any value, the entire cervical spine must be clearly seen. A CT scan of the cervical spine taken immediately following the cervical spine radiograph is shown on the right. This reveals anterior fractures of C1 (white arrows), fractures of the body of C5 (yellow arrow), a fracture of the dens of C2 (blue arrow), and a complex fracture of the left C5-6 facet joint (red arrow) that were not appreciated on the plain film. Choice of the technique used to introduce an endotracheal tube must take into account the stability of the cervical spine.
Image courtesy of Lennard A. Nadalo, MD.
On a lateral cervical spine radiograph taken following an automobile accident (left), the C6-C7 level is poorly seen due to the patient's shoulders. An axial CT scan through this area (right) reveals an unstable fracture of the left C6/C7 facet and pedicle. While some unstable cervical spine injuries can be surgically managed on a delayed basis (if cord compression is not present), other injuries, such as a bilateral facet dislocation, usually need to be managed acutely.
Image courtesy of Lennard A. Nadalo, MD.
A lateral cervical spine radiograph following neck trauma (left) shows fracture with distraction of the spinous process of C7 (white arrow). This type of injury was originally associated with clay shoveling and is known as the "clay-shoveler's fracture." Other activities that place sudden or extreme stress on the spinous processes of the lower cervical spine may result in a similar injury. A CT scan through the level of C7 (right) shows a fracture of the C7 spinous process (white arrow), confirming the findings on the lateral radiograph.
Image courtesy of Lennard A. Nadalo, MD.
A lateral cervical spine radiograph (left) demonstrates a C6 compression fracture (white arrow) with a subtle posterior subluxation and an abnormal curvature. A lateral cervical spine radiograph taken from another case, following a motor vehicle accident (right), shows a teardrop fracture of C5 (white arrow). Teardrop fractures occur when there is vertical axial compression associated with flexion, causing a fracture of the anterior-inferior aspect of the vertebral body.[11] Teardrop fractures are severe, unstable injuries of the cervical spine. The teardrop fracture fragment becomes displaced anteriorly. The vertebral body is displaced posteriorly into the spinal canal due to fracture of the posterior spinal elements and disruption of the ligamentum flavum and interspinous ligaments. This highly unstable fracture pattern is associated with a high incidence of spinal cord trauma.
Image courtesy of Lennard A. Nadalo, MD.
It is important to evaluate all of the structures in the field of view. This lateral cervical spine radiograph, taken following a motor vehicle accident, demonstrates a fracture of the mandible (black arrow) and a hangman's fracture of C2 (white arrow). Note the endotracheal tube anterior to the cervical spine. Hangman's fractures, which are bilateral fractures through the pedicles of C2, are caused by hyperextension. Although they represent the typical fracture pattern seen after a hanging, hangman's fractures most commonly result from motor vehicle collisions. They are unstable injuries but are less often associated with spinal cord trauma.[12,13]
Image courtesy of Lennard A. Nadalo, MD.
Although radiographs are very good at revealing injuries, not all fractures will be detected by conventional radiography. The cervical spine radiograph (left) and cervical spine CT images (right) were taken in a patient following a motor vehicle accident. The radiograph demonstrates a vertical defect (yellow arrow) that is consistent with a C3 fracture. The vertical fracture resulted from a force applied to the superior-anterior C3 body. On the CT scan, in addition to the C3 fracture (yellow arrow), an anterior-lateral fracture of C2 (white arrow) is seen. CT imaging is highly accurate in the detection of cervical spine fractures and can aid in therapeutic planning.
Image courtesy of Lennard A. Nadalo, MD.
Close evaluation of the spaces between vertebrae is necessary to detect ligamentous injury. This lateral cervical spine radiograph was taken following a motorcycle injury. The exam demonstrates widening of the intervertebral body distance anteriorly (white arrow) and posteriorly (red dots), as well as separation of the spinous processes of C5-C6 (yellow, double-headed arrow). The distances between the spinous processes of the midcervical spine and lower cervical spine should be nearly equal. Widening between the spinous processes indicates disruption of the interspinous ligaments. The disruption of the middle and posterior articulations of the cervical spine indicates an unstable injury.
Image courtesy of Lennard A. Nadalo, MD.
Careful evaluation of the cervical columns will readily identify subluxation and dislocation injuries. This lateral radiograph shows forward anterior subluxation of C4 over C5 (yellow arrow), with associated widening to the posterior interspinous space (white arrow) that is consistent with ligament disruption. This injury occurs due to hyperflexion of the cervical spine with a forward translation of the C4 vertebral body over C5. All three columns of the cervical spine are disrupted, resulting in instability. There was cervical cord injury in this case. Surgical stabilization was performed in mild extension.
Image courtesy of Lennard A. Nadalo, MD.
Oblique radiographs of the cervical spine are obtained in order to review the cervical spine foramina. The right oblique view of the cervical spine on the left demonstrates the normal smooth margins of the cervical neuroforamina (white arrows). The uncovertebral joints form the anterior margins of the neuroforamina on this view (black arrows). The right oblique view seen on the right shows the effects of degenerative hypertrophy of the uncovertebral joints, with stenosis of the lower foramina resulting from osteophytes. The upper foramen demonstrates the normal smoothly marginated, oval shape of the unaffected foramen.
Image courtesy of Lennard A. Nadalo, MD.
The use of an oblique film can help to locate structures that are within the central cervical spine and establish the trajectory of ballistic injuries. This oblique cervical spine radiograph was taken in a patient following an assault. The tip of a blade was driven into the spine (black arrow), resulting in partial paralysis. In questionable cases, CT scanning of the cervical spine should be performed.
Image courtesy of Lennard A. Nadalo, MD.
Flexion-extension views assess the functional stability of injuries to the cervical spine. Significant injuries masked on an image taken in the neutral position may be readily apparent on flexion or extension views. Normal upright radiographic studies, above, were obtained on a child following an accident in a school yard. In flexion (left), the cervical spine is straight. In extension (right), the normal cervical curve is demonstrated, with preservation of the cervical columns.
Image courtesy of Lennard A. Nadalo, MD.
This elderly patient, with no history of trauma, experienced neck pain with movement. Normal alignment is demonstrated on the extension view (left). On the flexion view (right), however, there is disruption of the middle column, with movement of C3 anterior to C4 (yellow lines), consistent with a ligamentous disease. Chronic degenerative changes of the facet joints and the supporting spinal ligaments may result in moderate cervical spinal instability, as in this case.
Image courtesy of Lennard A. Nadalo, MD.
This lateral radiographic view from a teenager involved in a motor vehicle accident, taken in a neutral position (left), demonstrates a possible increase in the distance between the dens of C2 and the anterior arch of C1 (white, double-headed arrow), measuring 4 mm. The predental distance to C1 should be less than 3 mm in an adult but may be somewhat greater in a child. The lateral flexion cervical spine radiograph (right) shows an increase in the predental distance (black, double-headed arrow) to greater than 5 mm. This is consistent with instability and probable ligamentous injury; the patient was treated with surgical stabilization of the C1-C2 interspace. Thus, the evaluation of the C1-C2 distance is useful in the assessment of acute upper cervical spine injury. When the AP distance between C1-C2 is 3 mm or less, the C1-C2 articulation is most likely intact.
Image courtesy of Lennard A. Nadalo, MD.
On an AP cervical spine radiograph, the spinous processes (yellow dots) should be in alignment and of nearly equal distance (yellow lines). The spinous process of C7 is indicated on this image (white arrow). The facet joints and airway should also be in the midline. The use of intersegmental measurements allows for rapid assessment of cervical alignment and probable stability without excessive patient repositioning.
Image courtesy of Lennard A. Nadalo, MD.
Open-mouth AP views of the odontoid provide an alternative view of the dens to be compared with the lateral cervical spine view. Fractures of the dens are divided into type I (if they avulse the tip), type II (if they occur at the base),[14] and type III (if they extend through the body of the axis). Type II and III fractures are considered unstable. The radiograph (left) demonstrates a nondisplaced fracture of the base of the dens (white arrow). A nondisplaced fracture or a vertical fracture may be difficult to see on the AP view alone. A CT scan of the same patient (right) also demonstrates a vertical oblique fracture of the dens (black arrow).
Image courtesy of Lennard A. Nadalo, MD.
Axial loading, usually from a diving injury, can lead to a burst fracture of the C1 vertebra, termed a Jefferson fracture.[15] The C1 vertebra is most commonly a closed ring. Fractures of C1 often occur in multiples. Fractures of the C1 ring can be identified by lateral displacement (white arrows) on an open-mouth AP view. These are unstable fractures requiring stabilization.
Image courtesy of Lennard A. Nadalo, MD.
Hardware used to stabilize fractures may complicate radiography of the cervical spine. A lateral view of the cervical spine following anterior and posterior fixation (left) shows pedicle screws (white arrows) and an anterior plate, which were needed to repair an unstable injury. A bone graft (yellow arrow) is noted in secure position in the anterior C5-6 interspace. Another lateral view of the cervical spine (right) demonstrates posterior fixation of C1 and C2 using wires (white arrow).[16]
Image courtesy of Lennard A. Nadalo, MD.
Cervical spine radiographs are often used to confirm that an anterior fixation cervical spine fusion performed with interposition grafts remains stable and secure. The interposition grafts are marked by vertically oriented markers, as seen here. These grafts must remain in position between the vertebral bodies. Screws used to place an anterior metal plate should be flush with the plate. In this case, an anterior screw (white arrow) is not fully engaged against the plate, and the upper portion of the anterior plate is not flush against the anterior margin of C3. Follow-up studies are often performed with a lateral flexion-extension technique in order to verify the stability of cervical spine fusion procedures. Comparison with prior radiographic and CT-scan cervical examinations is very helpful in the early identification of postoperative complications.
Image courtesy of Lennard A. Nadalo, MD.
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