SternoClavicular Joint Injury: What You Need to Know

The sternoclavicular (SC) joint is the only true joint that connects the upper arm and the chest. It is located at the base of the neck, where the collarbone (clavicle) meets the breastbone (sternum). Injuries to this joint are rare, but they can be serious and cause pain, swelling, and reduced shoulder movement. In this article, we will explain the causes, symptoms, diagnosis, and treatment of SC joint injuries.

 

ANATOMY (FIG. 12.4)

The SC joint is a diarthrodial joint, representing the only true articulation between the upper
extremity and the axial skeleton.

 The articular surface of the clavicle is much larger than that of the sternum; both are covered
with fibrocartilage. Less than half of the medial clavicle articulates with the sternum; thus,

the SC joint has the distinction of having the least amount of bony stability of the major
joints of the body.

 Joint integrity is derived from the saddle-like configuration of the joint (convex vertically and
concave anteroposteriorly) as well as from surrounding ligaments:

 The intra-articular disc ligament is a checkrein against medial displacement of the
clavicle.

 The extra-articular costoclavicular ligament resists rotation and medial–lateral
displacement.

 The interclavicular ligament helps to maintain shoulder poise.

 Range of motion is 35 degrees of superior elevation, 35 degrees of combined AP motion, and

50 degrees of rotation around its long axis.

 The medial clavicle physis is the last physis to close. It ossifies at 20 years and fuses with the

shaft at 25 to 30 years. Therefore, many supposed SC joint dislocations may actually be
physeal injuries.

FIGURE 12.4 Cross sections through the thorax at the level of the SC joint. (A) Normal anatomic relations. (B)Posterior dislocation of the SC. (C) Anterior dislocation of the SC.

 

 

 

 

 

 

 

MECHANISM OF INJURY (FIG. 12.5)

 Direct: Force applied to the anteromedial aspect of the clavicle forces the clavicle posteriorly
into the mediastinum to produce posterior dislocation. This may occur when an athlete is in

the supine position and another athlete falls on him or her, when an individual is run over by
a vehicle, or when an individual is pinned against a wall by a vehicle.

 Indirect: Force can be applied indirectly to the SC joint from the anterolateral (producing
anterior SC dislocation) or posterolateral (producing posterior SC dislocation) aspects of the

shoulder. This is most commonly seen in football “pileups,” in which an athlete is lying
obliquely on his or her shoulder and force is applied with the individual unable to change
position.

FIGURE 12.5 Mechanisms that produce anterior or posterior dislocations of the SC joint. (A) If the patient is lying on the ground and compression force is applied to the posterolateral aspect of the shoulder, the medial end of the clavicle will be displaced posteriorly. (B) When the lateral compression force is directed from the anterior position, the medial end of the clavicle is dislocated anteriorly. (From Edgar C. Acromioclavicular

CLINICAL EVALUATION

 The patient typically presents supporting the affected extremity across the trunk with the
contralateral, uninjured arm. The patient’s head may be tilted toward the side of injury to

decrease stress across the joint, and the patient may be unwilling to place the affected
scapula flat on the examination table.

 Swelling, tenderness, and painful range of shoulder motion are usually present, with a
variable change of the medial clavicular prominence, depending on the degree and direction

of injury.

 Neurovascular status must be assessed because the brachial plexus and major vascular

structures are in the immediate vicinity of the medial clavicle.

 With posterior dislocations, venous engorgement of the ipsilateral extremity, shortness of

breath, painful inspiration, difficulty swallowing, and a choking sensation may be present.
The chest must be auscultated to ensure bilaterally symmetric breath sounds.

 

RADIOGRAPHIC EVALUATION

 AP chest radiographs typically demonstrate asymmetry of the clavicles that should prompt
further radiographic evaluation. This view should be scrutinized for the presence of

pneumothorax if the patient presents with breathing complaints.

 Hobbs view: In this 90-degree cephalocaudal lateral view, the patient leans over the plate,

and the radiographic beam is angled behind the neck (Fig. 12.6).

FIGURE 12.6 Hobbs view: positioning of the patient for x-ray evaluation of the SC joint, as recommended
by Hobbs. (From Edgar C. Acromioclavicular and sternoclavicular joint injuries. In: Tornetta P III, Ricci
WM, Ostrum RF, et al., eds. Rockwood and Green’s Fractures in Adults. Vol 1. 9th ed. Philadelphia: Wolters
Kluwer; 2020:917–975.)

 Serendipity view: This 40-degree cephalic tilt view is aimed at the manubrium. With an
anterior dislocation, the medial clavicle lies above the interclavicular line; with a posterior

dislocation, the medial clavicle lies below this line (Fig. 12.7).

 

FIGURE 12.7 Serendipity view: positioning of the patient to take the “serendipity” view of the SC joints.
The x-ray tube is tilted 40 degrees from the vertical position and is aimed directly at the manubrium. The
nongrid cassette should be large enough to receive the projected images of the medial halves of both clavicles.
In children, the tube distance from the patient should be 45 inches; in thicker chested adults, the distance
should be 60 inches. (From Edgar C. Acromioclavicular and sternoclavicular joint injuries. In: Tornetta P III,
Ricci WM, Ostrum RF, et al., eds. Rockwood and Green’s Fractures in Adults. Vol 1. 9th ed. Philadelphia:
Wolters Kluwer; 2020:917–975.)

   CT scan: This is the best technique to evaluate injuries to the SC joint. CT is able to
distinguish fractures of the medial clavicle from dislocation as well as delineate minor

subluxations that would otherwise go unrecognized.

 

CLASSIFICATION

Anatomic

   Anterior dislocation: more common    Posterior dislocation

 

Etiologic

   Sprain or subluxation

   Mild: joint stable, ligamentous integrity maintained
   Moderate: subluxation, with partial ligamentous disruption
   Severe: unstable joint, with complete ligamentous compromise

   Acute dislocation: complete ligamentous disruption with frank translation of the medial
clavicle

   Recurrent dislocation: rare

   Unreduced dislocation

   Atraumatic: may occur with spontaneous dislocation, developmental (congenital)

dislocation, osteoarthritis, condensing osteitis of the medial clavicle, SC hyperostosis, or
infection

 

TREATMENT

   Mild sprain: Ice is indicated for the first 24 hours with sling immobilization for 3 to 4 days
and a gradual return to normal activities as tolerated.

   Moderate sprain or subluxation: Ice is indicated for the first 24 hours with a clavicle strap,
sling and swathe, or figure-of-eight bandage for 1 week and then sling immobilization for 4

to 6 weeks.

 Severe sprain or dislocation (Fig. 12.8)

 Medial physeal injury: Closed reduction is usually successful, with postreduction care
consisting of a clavicle strap, sling and swathe, or figure-of-eight bandage immobilization

for 4 to 6 weeks.

 Operative management of SC dislocation may include fixation of the medial clavicle to the

sternum using fascia lata, subclavius tendon, or suture; osteotomy of the medial clavicle; or resection of the medial clavicle. The use of Kirschner wires or Steinmann pins is
discouraged because migration of hardware may occur.

 

COMPLICATIONS

 Poor cosmesis is the most common complication with patients complaining of an enlarged
medial prominence.

 Complications are more common with posterior dislocations and reflect the proximity of the
medial clavicle to mediastinal and neurovascular structures. The complication rate has been
reported to be as high as 25% with posterior dislocation. Complications include the

following:
 Pneumothorax

 Laceration of the superior vena cava
 Venous congestion in the neck
 Esophageal rupture

 Subclavian artery compression
 Carotid artery compression

 Voice changes

 

 

 

 

 

sternoclavicular joint injury

SC joint injury

sprain

subluxation

dislocation

treatment