·         Normally, about 50% of the medial end of the clavicle articulates with the manubrium of the sternum

·         Joint is freely movable synovial joint

·         Sternoclavicular dislocations are one of the rarest dislocations to occur

o       Strength of the sternoclavicular ligaments

·         Requires considerable force

o       Usually a direct or indirect blow to the shoulder or shoulder region

·         Most commonly occurs from motor vehicle collisions,  followed by athletic injuries and falls

·         Sprains are more common than subluxations or dislocations

·         Of dislocations, anterior dislocation of the clavicular head is 9 times more common than posterior dislocations

o       Usually caused by a force that drives shoulder backwards and clavicular head forward

o       Posterior blows to the shoulder region may drive the shoulder forward and the clavicular head posteriorly

§         Or direct impact on the head of the clavicle may drive it backward

·         Co-morbidity is unusual in anterior dislocations but occurs in about 25% of posterior dislocations

o       Complications can include

§         Pneumothorax

§         Superior vena caval laceration

§         Subclavian artery or vein occlusion

§         Tracheal rupture

§         Death

·         Imaging

o       Conventional radiography

§         Chest x-rays may be normal, even with a dislocation

§         Special views of the clavicles may help

·         Serendipity view is an AP view of the clavicles with the tube angled upward by 40° in the supine position

·         Normally, the medial ends of the clavicles are at the same level

·         Since this is in essence an apical lordotic view, an anteriorly dislocated clavicular head will appear higher than the normal side whereas a posteriorly dislocated clavicular head will appear lower than the normal side

o       CT is the study of choice

 

Posterior sternoclavicular dislocation. Chest radiograph demonstrates an unequal position of the heads of the clavicles with the right side (yellow arrow) being higher than the left (green arrow). In a patient with significant trauma, this is an alert to the presence of a dislocation of the medial end of the clavicle. The CT scan (bottom) shows the normally articulating right clavicular head (yellow arrow) and the posteriorly dislocated left clavicular head (green arrow). The light blue arrow points to the manubrium of the sternum.
For a photo of the same image without arrows, click here

 

·         Treatment

o       Anteriorly dislocated clavicular heads can be treated without surgery

o       Reduction of a posterior dislocation frequently requires general anesthesia but closed reduction may fail and require open reduction and internal fixation