Laboratory Studies
Laboratory studies are generally not necessary for the diagnosis of cervical spine strain/sprain injuries.
Imaging Studies
Plain radiographs
In cervical spine trauma, routine radiography remains the initial imaging study of choice. Cervical spine radiographs should be obtained unless the history is clearly one of overuse. Of note, the microscopic damage that occurs as a result of a suspected whiplash syndrome or impulse loading due to athletic activity may not be seen on routine imaging studies.
A cervical spine series usually includes anteroposterior (AP), lateral, oblique, and odontoid views. [15] All 7 vertebrae must be visualized, and the disc spaces should be approximately equal throughout the cervical spine.
The lateral view is useful for assessing alignment and soft-tissue swelling. The normal distance between the front of C3-C5 and the tracheal shadow is 5 mm in the adult. An increase in this distance suggests soft-tissue swelling and significant injury.
The posterior borders of the vertebral bodies should lie in a relatively straight line that gently curves in a lordotic direction. Lines drawn through the horizontal axis of each spinous process should converge on a point well posterior to the spine when normal cervical lordosis is present. Loss of lordosis implies muscle spasm, whereas loss of convergence implies potential instability. A step-off in the alignment of the vertebral bodies may indicate either a facet subluxation or dislocation or a posterior element fracture.
The lateral view is also useful in assessing the stability of C1 on C2. A space greater than 2-3 mm between the anterior border of the odontoid process and the adjacent posterior border of the anterior ring of C1 suggests abnormal mobility of C1, which can be due to an odontoid fracture or transverse ligament rupture. Lateral radiographs that demonstrate more than 11° of rotation from either adjacent vertebra or demonstrate more than 3.5 mm of horizontal displacement between any one vertebra in relationship to another represent an absolute contraindication to further participation in contact activities.
The odontoid or open-mouth view demonstrates the odontoid in the AP direction. The distances between the odontoid and the horizontal portions of the ring of C1 on each side should be equal. If these distances are not equal, a rotary subluxation may be present.
The oblique view best shows the facet joints and the neural foramina. If the radiographs reveal any evidence of fracture, dislocation, or subluxation, the patient's neck should be immobilized and the patient should be immediately referred to an orthopedist or neurosurgeon. If the initial static radiographs are normal, flexion-extension lateral views should be obtained once the acute symptoms have subsided. Note that in acute trauma cases, flexion-extension radiographs should be avoided, because during flexion-extension maneuvers, iatrogenic neurologic injuries may result. Flexion-extension views are valuable after acute trauma in revealing ligamentous subacute instability.
Computed tomography (CT) scanning
CT scanning is performed in patients who have abnormal plain radiographs or in whom there is a strong clinical suspicion of a fracture with inconclusive radiographs. [15, 16]
Disruptions of the vertebral body or lamina, fractures of the facet joint, and fragments of intracanal bone are better shown by CT scan studies, particularly with reconstructed images. Multiplanar display, with reformation into sagittal or coronal projections, can greatly enhance demonstrations of fractures and other lesions that are not optimally shown in the transaxial plane or that cover relatively long areas.
CT scanning remains the imaging study of choice to evaluate traumatic bony lesions of the cervical spine.
Magnetic resonance imaging (MRI)
MRI is usually indicated in athletes with neurologic deficits and when plain radiographic films and CT scans do not provide enough information for definitive management.
MRI is useful in the diagnosis of cord and nerve root injury in patients who are neurologically compromised.
Advantages of MRI include the ability to detect soft-tissue and spinal cord abnormalities, such as disc herniation, ligamentous disruption, hematoma, cord hemorrhage or edema, and syringomyelia.
MRI or bone scintigraphy may be indicated in cases in which patients have continuing limitation of motion, pain, or radicular symptoms.
Related Medscape Reference topics include the following:
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Bony framework of head and neck.
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Cervical vertebrae, the atlas and the axis.
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Cervical vertebrae.
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External craniocervical ligaments.
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Internal craniocervical ligaments.
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Atlantooccipital junction.
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Lateral view of the muscles of the neck.
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Anterior view of the muscles of the neck.
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Infrahyoid and suprahyoid muscles.
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Scalene and prevertebral muscles.
