Imaging Studies
Routine radiographs of the sternoclavicular joint are often difficult to interpret and may falsely appear normal. [6, 7, 8]
A specialized view, known as the serendipity view and described by Rockwood, may reveal the medial clavicle position. [9] For this technique, the beam is tilted to 40° from vertical and directed cephalad through the manubrium of the patient while in a supine position. Normal clavicles should appear in the same horizontal plane, while anterior and posterior dislocations appear above and below the plane, respectively. [2]
In the Hobbs view, the patient sits at the radiography table and leans forward so that the anterior chest is in contact with the film cassette and the flexed elbows straddle the cassette and support the patient. The x-ray beam is aimed directly down through the cervical spine, projecting the sternoclavicular joints onto the film cassette.
CT scanning is an excellent technique to study problems of the sternoclavicular joint. Request inclusion of both sternoclavicular joints and the medial half of both clavicles on the CT scan so that the injured side can be compared with the noninjured side. In addition to revealing the position of the medial clavicle, the CT scan provides important information about the vital tissues of the superior mediastinum, which may be concomitantly injured. [10]
In a study to assess digital tomography in SCJ pathology, of 102 patients who had digital tomography as their initial investigation, the most common diagnoses identified included osteoarthritis, fracture, and dislocation, and only 18 patients required further investigation by CT or MRI to make the diagnosis. [11]
(See the images below.)
CT scan of a left sternoclavicular dislocation demonstrates anterior and superior displacement of the clavicle from its normal articulation with the manubrium. The right sternoclavicular joint is normal.
CT scan of a left sternoclavicular dislocation demonstrates anterior and superior displacement of the clavicle from its normal articulation with the manubrium. The right sternoclavicular joint is normal.
CT scan of a left sternoclavicular dislocation demonstrates anterior and superior displacement of the clavicle from its normal articulation with the manubrium. The right sternoclavicular joint is normal.
Other imaging studies, such as angiography or esophagoscopy, may be indicated when mediastinal injuries from a posterior dislocation are suspected.
MRI provides similar information as a CT scan while better documenting the soft tissue anatomy and associated mediastinal structures, but availability is often limited for emergency patients. Relative cost is also a consideration.
Bedside ultrasound may be used to evaluate bony contours and structural alignment, and the sternoclavicular joint space, a small hypoechoic area, may be identified between the clavicle and sternum. Adjacent vascular structures and their flow may be assessed, and the presence of a hemothorax or pneumothorax may also be diagnosed. Typically, a high frequency (7-13) MHz linear-array probe is used, aligned parallel to the clavicular long axis. [27, 28]
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This 80-year-old woman presented 1 week after a fall because of persistent pain and discoloration in the anterior part of her chest. Certain movements of her right arm were especially painful though not incapacitating. Note the extensive ecchymosis of the anterior part of her thorax and the swelling of the right upper parasternal/lower anterior neck area. The right sternoclavicular joint area was tender and edematous to palpation.
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Superior mediastinal contents may be threatened in posterior dislocations of the sternoclavicular joint.
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CT scan of a left sternoclavicular dislocation demonstrates anterior and superior displacement of the clavicle from its normal articulation with the manubrium. The right sternoclavicular joint is normal.
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CT scan of a left sternoclavicular dislocation demonstrates anterior and superior displacement of the clavicle from its normal articulation with the manubrium. The right sternoclavicular joint is normal.
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CT scan of a left sternoclavicular dislocation demonstrates anterior and superior displacement of the clavicle from its normal articulation with the manubrium. The right sternoclavicular joint is normal.
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The right sternoclavicular joint appears edematous on lateral inspection. Palpation confirms the apparent anterior dislocation.
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Comparison of the normal left sternoclavicular joint emphasizes the abnormalities.
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The patient refused further workup and treatment beyond a temporary sling, stating that the injury had not significantly affected her lifestyle. She was discharged home in the company of her daughter with over-the-counter analgesics.
